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 | | http://functions.wolfram.com/04.08.06.0002.01 | 
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 | | GCD[m, n] == 1 - 2 Floor[m/2] Floor[n/2] - KroneckerDelta[m/2 - Floor[m/2]] 
   KroneckerDelta[n/2 - Floor[n/2]] + 
  2 Sum[Floor[(k n)/m], {k, 1, Floor[m/2]}] + 
  2 Sum[Floor[(k m)/n], {k, 1, Floor[n/2]}] | 
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 | | Cell[BoxData[RowBox[List[RowBox[List["GCD", "[", RowBox[List["m", ",", "n"]], "]"]], "\[Equal]", RowBox[List["1", "-", RowBox[List["2", " ", RowBox[List["Floor", "[", FractionBox["m", "2"], "]"]], " ", RowBox[List["Floor", "[", FractionBox["n", "2"], "]"]]]], "-", RowBox[List[RowBox[List["KroneckerDelta", "[", RowBox[List[FractionBox["m", "2"], "-", RowBox[List["Floor", "[", FractionBox["m", "2"], "]"]]]], "]"]], RowBox[List["KroneckerDelta", "[", RowBox[List[FractionBox["n", "2"], "-", RowBox[List["Floor", "[", FractionBox["n", "2"], "]"]]]], "]"]]]], "+", RowBox[List["2", " ", RowBox[List[UnderoverscriptBox["\[Sum]", RowBox[List["k", "=", "1"]], RowBox[List["Floor", "[", FractionBox["m", "2"], "]"]]], RowBox[List["Floor", "[", FractionBox[RowBox[List["k", " ", "n"]], "m"], "]"]]]]]], "+", RowBox[List["2", " ", RowBox[List[UnderoverscriptBox["\[Sum]", RowBox[List["k", "=", "1"]], RowBox[List["Floor", "[", FractionBox["n", "2"], "]"]]], RowBox[List["Floor", "[", FractionBox[RowBox[List["k", " ", "m"]], "n"], "]"]]]]]]]]]]]] | 
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   <math xmlns='http://www.w3.org/1998/Math/MathML' mathematica:form='TraditionalForm' xmlns:mathematica='http://www.wolfram.com/XML/'>  <semantics>  <mrow>  <mrow>  <mi> gcd </mi>  <mo> ⁡ </mo>  <mo> ( </mo>  <mrow>  <mi> m </mi>  <mo> , </mo>  <mi> n </mi>  </mrow>  <mo> ) </mo>  </mrow>  <mo> ⩵ </mo>  <mrow>  <mn> 1 </mn>  <mo> - </mo>  <mrow>  <mn> 2 </mn>  <mo> ⁢ </mo>  <mrow>  <mo> ⌊ </mo>  <mfrac>  <mi> m </mi>  <mn> 2 </mn>  </mfrac>  <mo> ⌋ </mo>  </mrow>  <mo> ⁢ </mo>  <mrow>  <mo> ⌊ </mo>  <mfrac>  <mi> n </mi>  <mn> 2 </mn>  </mfrac>  <mo> ⌋ </mo>  </mrow>  </mrow>  <mo> - </mo>  <mrow>  <msub>  <semantics>  <mi> δ </mi>  <annotation-xml encoding='MathML-Content'>  <ci> KroneckerDelta </ci>  </annotation-xml>  </semantics>  <mrow>  <mfrac>  <mi> m </mi>  <mn> 2 </mn>  </mfrac>  <mo> - </mo>  <mrow>  <mo> ⌊ </mo>  <mfrac>  <mi> m </mi>  <mn> 2 </mn>  </mfrac>  <mo> ⌋ </mo>  </mrow>  </mrow>  </msub>  <mo> ⁢ </mo>  <msub>  <semantics>  <mi> δ </mi>  <annotation-xml encoding='MathML-Content'>  <ci> KroneckerDelta </ci>  </annotation-xml>  </semantics>  <mrow>  <mfrac>  <mi> n </mi>  <mn> 2 </mn>  </mfrac>  <mo> - </mo>  <mrow>  <mo> ⌊ </mo>  <mfrac>  <mi> n </mi>  <mn> 2 </mn>  </mfrac>  <mo> ⌋ </mo>  </mrow>  </mrow>  </msub>  </mrow>  <mo> + </mo>  <mrow>  <mn> 2 </mn>  <mo> ⁢ </mo>  <mrow>  <munderover>  <mo> ∑ </mo>  <mrow>  <mi> k </mi>  <mo> = </mo>  <mn> 1 </mn>  </mrow>  <mrow>  <mo> ⌊ </mo>  <mfrac>  <mi> m </mi>  <mn> 2 </mn>  </mfrac>  <mo> ⌋ </mo>  </mrow>  </munderover>  <mrow>  <mo> ⌊ </mo>  <mfrac>  <mrow>  <mi> k </mi>  <mo> ⁢ </mo>  <mi> n </mi>  </mrow>  <mi> m </mi>  </mfrac>  <mo> ⌋ </mo>  </mrow>  </mrow>  </mrow>  <mo> + </mo>  <mrow>  <mn> 2 </mn>  <mo> ⁢ </mo>  <mrow>  <munderover>  <mo> ∑ </mo>  <mrow>  <mi> k </mi>  <mo> = </mo>  <mn> 1 </mn>  </mrow>  <mrow>  <mo> ⌊ </mo>  <mfrac>  <mi> n </mi>  <mn> 2 </mn>  </mfrac>  <mo> ⌋ </mo>  </mrow>  </munderover>  <mrow>  <mo> ⌊ </mo>  <mfrac>  <mrow>  <mi> k </mi>  <mo> ⁢ </mo>  <mi> m </mi>  </mrow>  <mi> n </mi>  </mfrac>  <mo> ⌋ </mo>  </mrow>  </mrow>  </mrow>  </mrow>  </mrow>  <annotation-xml encoding='MathML-Content'>  <apply>  <eq />  <apply>  <gcd />  <ci> m </ci>  <ci> n </ci>  </apply>  <apply>  <plus />  <cn type='integer'> 1 </cn>  <apply>  <times />  <cn type='integer'> -1 </cn>  <apply>  <times />  <cn type='integer'> 2 </cn>  <apply>  <floor />  <apply>  <times />  <ci> m </ci>  <apply>  <power />  <cn type='integer'> 2 </cn>  <cn type='integer'> -1 </cn>  </apply>  </apply>  </apply>  <apply>  <floor />  <apply>  <times />  <ci> n </ci>  <apply>  <power />  <cn type='integer'> 2 </cn>  <cn type='integer'> -1 </cn>  </apply>  </apply>  </apply>  </apply>  </apply>  <apply>  <times />  <cn type='integer'> -1 </cn>  <apply>  <times />  <apply>  <ci> KroneckerDelta </ci>  <apply>  <plus />  <apply>  <times />  <ci> m </ci>  <apply>  <power />  <cn type='integer'> 2 </cn>  <cn type='integer'> -1 </cn>  </apply>  </apply>  <apply>  <times />  <cn type='integer'> -1 </cn>  <apply>  <floor />  <apply>  <times />  <ci> m </ci>  <apply>  <power />  <cn type='integer'> 2 </cn>  <cn type='integer'> -1 </cn>  </apply>  </apply>  </apply>  </apply>  </apply>  </apply>  <apply>  <ci> KroneckerDelta </ci>  <apply>  <plus />  <apply>  <times />  <ci> n </ci>  <apply>  <power />  <cn type='integer'> 2 </cn>  <cn type='integer'> -1 </cn>  </apply>  </apply>  <apply>  <times />  <cn type='integer'> -1 </cn>  <apply>  <floor />  <apply>  <times />  <ci> n </ci>  <apply>  <power />  <cn type='integer'> 2 </cn>  <cn type='integer'> -1 </cn>  </apply>  </apply>  </apply>  </apply>  </apply>  </apply>  </apply>  </apply>  <apply>  <times />  <cn type='integer'> 2 </cn>  <apply>  <sum />  <bvar>  <ci> k </ci>  </bvar>  <lowlimit>  <cn type='integer'> 1 </cn>  </lowlimit>  <uplimit>  <apply>  <floor />  <apply>  <times />  <ci> m </ci>  <apply>  <power />  <cn type='integer'> 2 </cn>  <cn type='integer'> -1 </cn>  </apply>  </apply>  </apply>  </uplimit>  <apply>  <floor />  <apply>  <times />  <ci> k </ci>  <ci> n </ci>  <apply>  <power />  <ci> m </ci>  <cn type='integer'> -1 </cn>  </apply>  </apply>  </apply>  </apply>  </apply>  <apply>  <times />  <cn type='integer'> 2 </cn>  <apply>  <sum />  <bvar>  <ci> k </ci>  </bvar>  <lowlimit>  <cn type='integer'> 1 </cn>  </lowlimit>  <uplimit>  <apply>  <floor />  <apply>  <times />  <ci> n </ci>  <apply>  <power />  <cn type='integer'> 2 </cn>  <cn type='integer'> -1 </cn>  </apply>  </apply>  </apply>  </uplimit>  <apply>  <floor />  <apply>  <times />  <ci> k </ci>  <ci> m </ci>  <apply>  <power />  <ci> n </ci>  <cn type='integer'> -1 </cn>  </apply>  </apply>  </apply>  </apply>  </apply>  </apply>  </apply>  </annotation-xml>  </semantics>  </math> 
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 | | Cell[BoxData[RowBox[List[RowBox[List["HoldPattern", "[", RowBox[List["GCD", "[", RowBox[List["m_", ",", "n_"]], "]"]], "]"]], "\[RuleDelayed]", RowBox[List["1", "-", RowBox[List["2", " ", RowBox[List["Floor", "[", FractionBox["m", "2"], "]"]], " ", RowBox[List["Floor", "[", FractionBox["n", "2"], "]"]]]], "-", RowBox[List[RowBox[List["KroneckerDelta", "[", RowBox[List[FractionBox["m", "2"], "-", RowBox[List["Floor", "[", FractionBox["m", "2"], "]"]]]], "]"]], " ", RowBox[List["KroneckerDelta", "[", RowBox[List[FractionBox["n", "2"], "-", RowBox[List["Floor", "[", FractionBox["n", "2"], "]"]]]], "]"]]]], "+", RowBox[List["2", " ", RowBox[List[UnderoverscriptBox["\[Sum]", RowBox[List["k", "=", "1"]], RowBox[List["Floor", "[", FractionBox["m", "2"], "]"]]], RowBox[List["Floor", "[", FractionBox[RowBox[List["k", " ", "n"]], "m"], "]"]]]]]], "+", RowBox[List["2", " ", RowBox[List[UnderoverscriptBox["\[Sum]", RowBox[List["k", "=", "1"]], RowBox[List["Floor", "[", FractionBox["n", "2"], "]"]]], RowBox[List["Floor", "[", FractionBox[RowBox[List["k", " ", "m"]], "n"], "]"]]]]]]]]]]]] | 
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 | | Date Added to functions.wolfram.com (modification date) | 
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