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A061121 Number of degree-n permutations of order exactly 6. 23
0, 0, 0, 0, 20, 240, 1470, 10640, 83160, 584640, 4496030, 42658440, 371762820, 3594871280, 38650622010, 396457108320, 4330689250160, 53963701424640, 641211774798510, 8205894865096280, 113786291585124060 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,5

LINKS

Table of n, a(n) for n=1..21.

FORMULA

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

MATHEMATICA

nn=21; Range[0, nn]!CoefficientList[Series[(Exp[x^6/6]-1)Exp[x+x^2/2+x^3/3]+(Exp[x^2/2]-1)(Exp[x^3/3]-1)Exp[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: A163004 A278320 A061139 * A073398 A040075 A138442

Adjacent sequences:  A061118 A061119 A061120 * A061122 A061123 A061124

KEYWORD

easy,nonn

AUTHOR

Vladeta Jovovic, Apr 14 2001

STATUS

approved

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Last modified February 22 17:35 EST 2019. Contains 320400 sequences. (Running on oeis4.)