html, body, form { margin: 0; padding: 0; width: 100%; } #calculate { position: relative; width: 177px; height: 110px; background: transparent url(/images/alphabox/embed_functions_inside.gif) no-repeat scroll 0 0; } #i { position: relative; left: 18px; top: 44px; width: 133px; border: 0 none; outline: 0; font-size: 11px; } #eq { width: 9px; height: 10px; background: transparent; position: absolute; top: 47px; right: 18px; cursor: pointer; }

 Subfactorial

 http://functions.wolfram.com/06.42.26.0003.01

 Input Form

 Subfactorial[z] == HypergeometricU[-z, -z, -1] /; !(Element[z, Integers] && z > 1)

 Standard Form

 Cell[BoxData[RowBox[List[RowBox[List[RowBox[List["Subfactorial", "[", "z", "]"]], "\[Equal]", RowBox[List["HypergeometricU", "[", RowBox[List[RowBox[List["-", "z"]], ",", RowBox[List["-", "z"]], ",", RowBox[List["-", "1"]]]], "]"]]]], "/;", RowBox[List["Not", "[", RowBox[List[RowBox[List["Element", "[", RowBox[List["z", ",", "Integers"]], "]"]], "\[And]", RowBox[List["z", ">", "1"]]]], "]"]]]]]]

 MathML Form

 Subfactorial ( z ) U TagBox["U", HypergeometricU] ( - z , - z , - 1 ) /; ¬ ( z TagBox["\[DoubleStruckCapitalZ]", Function[List[], Integers]] z > 1 ) Condition Subfactorial z HypergeometricU -1 z -1 z -1 z z 1 [/itex]

 Rule Form

 Cell[BoxData[RowBox[List[RowBox[List["HoldPattern", "[", RowBox[List["Subfactorial", "[", "z_", "]"]], "]"]], "\[RuleDelayed]", RowBox[List[RowBox[List["HypergeometricU", "[", RowBox[List[RowBox[List["-", "z"]], ",", RowBox[List["-", "z"]], ",", RowBox[List["-", "1"]]]], "]"]], "/;", RowBox[List["!", RowBox[List["(", RowBox[List[RowBox[List["z", "\[Element]", "Integers"]], "&&", RowBox[List["z", ">", "1"]]]], ")"]]]]]]]]]]

 Date Added to functions.wolfram.com (modification date)

 2007-05-02