cp's OEIS Frontend

A245919 Number of pairs of endofunctions f, g on [n] satisfying f(g^10(i)) = f(i) for all i in [n].

%I A245919 #4 Aug 06 2014 15:46:24
%S A245919 1,1,12,249,7744,401625,30080736,3034643689,371205076992,
%T A245919 52680504366801,12762075858688000,4097222646625776921,
%U A245919 1485034580150268715008,546325401769976582587561,203541885180568005538811904,89218786842877518275107415625
%N A245919 Number of pairs of endofunctions f, g on [n] satisfying f(g^10(i)) = f(i) for all i in [n].
%H A245919 Alois P. Heinz, <a href="/A245919/b245919.txt">Table of n, a(n) for n = 0..150</a>
%p A245919 with(combinat):
%p A245919 b:= proc(n, i) option remember; unapply(`if`(n=0 or i=1, x^n,
%p A245919       expand(add((i-1)!^j*multinomial(n, n-i*j, i$j)/j!*
%p A245919       x^(igcd(i, 10)*j)*b(n-i*j, i-1)(x), j=0..n/i))), x)
%p A245919     end:
%p A245919 a:= n-> add(binomial(n-1, j-1)*n^(n-j)*b(j$2)(n), j=0..n):
%p A245919 seq(a(n), n=0..20);
%Y A245919 Column k=10 of A245910.
%K A245919 nonn
%O A245919 0,3
%A A245919 _Alois P. Heinz_, Aug 06 2014