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A102709 Let a(n,m) = card{f^(n) : f is a mapping from a set of m elements into itself}, where f^(l)(x) = f^(l-1)(f(x)),l>0, f^(0)(x) = x; sequence gives a(n,5). 7
1, 3125, 1075, 985, 580, 1281, 295, 1305, 580, 925, 631, 1305, 220, 1305, 655, 901, 580, 1305, 295, 1305, 556, 925, 655, 1305, 220, 1281, 655, 925, 580, 1305, 271, 1305, 580, 925, 655, 1281, 220, 1305, 655, 925, 556, 1305, 295, 1305, 580, 901, 655, 1305, 220 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Sequence appears to have a rational o.g.f. - Ralf Stephan, May 18 2007

LINKS

Ray Chandler, Table of n, a(n) for n = 0..10000

Index entries for linear recurrences with constant coefficients, signature (-1, -2, -2, -2, -1, 0, 1, 2, 2, 2, 1, 1).

FORMULA

Empirical g.f.: 1+x*(60*x^14 +480*x^13 +2360*x^12 +2584*x^11 +3099*x^10 +2188*x^9 -522*x^8 -4057*x^7 -8367*x^6 -9981*x^5 -12231*x^4 -9965*x^3 -8310*x^2 -4200*x -3125) / ((x -1)*(x +1)*(x^2 -x +1)*(x^2 +1)*(x^2 +x +1)*(x^4 +x^3 +x^2 +x +1)). - Colin Barker, Aug 07 2013

MATHEMATICA

Join[{1, 3125, 1075, 985}, LinearRecurrence[{-1, -2, -2, -2, -1, 0, 1, 2, 2, 2, 1, 1}, {580, 1281, 295, 1305, 580, 925, 631, 1305, 220, 1305, 655, 901}, 45]] (* Ray Chandler, Sep 08 2015 *)

CROSSREFS

Cf. A102687.

Row n=5 of A247026.

Sequence in context: A250523 A251061 A213193 * A057067 A223184 A084649

Adjacent sequences:  A102706 A102707 A102708 * A102710 A102711 A102712

KEYWORD

nonn

AUTHOR

Vladeta Jovovic, Feb 05 2005

EXTENSIONS

a(0) inserted by Alois P. Heinz, Sep 10 2014

STATUS

approved

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Last modified November 22 16:31 EST 2019. Contains 329396 sequences. (Running on oeis4.)