A061125 Number of degree-n permutations of order exactly 12.

0, 0, 0, 0, 0, 0, 420, 3360, 30240, 403200, 4019400, 80166240, 965284320, 12173441280, 162850287600, 2428557331200, 32123543612160, 534678700308480, 8126981741380320, 128338880777251200, 2080312367956502400, 36351373041072122880, 606331931399062693440

Offset

1,7

Links

Table of n, a(n) for n=1..23.

Formula

E.g.f.: exp(x + 1/2*x^2) - exp(x + 1/2*x^2 + 1/4*x^4) - exp(x + 1/2*x^2 + 1/3*x^3 + 1/6*x^6) + exp(x + 1/2*x^2 + 1/3*x^3 + 1/4*x^4 + 1/6*x^6 + 1/12*x^12).

Mathematica

nn=21; Range[0, nn]!CoefficientList[Series[(Exp[x^12/12]-1)Exp[x+x^2/2+x^3/3+x^4/4+x^6/6]+(Exp[x^6/6]-1)(Exp[x^4/4]-1)Exp[x+x^2/2+x^3/3]+(Exp[x^4/4]-1)(Exp[x^3/3]-1)Exp[x^2/2+x], {x, 0, nn}], x]//Rest  (* Geoffrey Critzer, Feb 04 2013 *)

Crossrefs

Cf. A000085, A001470, A001472, A052501, A053496 - A053505, A001189, A001471, A001473, A061121 - A061128.

Sequence in context: A145678 A160372 A171259 * A269016 A317983 A179718

Adjacent sequences: A061122 A061123 A061124 * A061126 A061127 A061128

Keyword

easy,nonn

Author

Vladeta Jovovic, Apr 14 2001

Status

approved