A061125 - OEIS

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

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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