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

1, 1, 12, 249, 7744, 401625, 30080736, 3034643689, 371205076992, 52680504366801, 12762075858688000, 4097222646625776921, 1485034580150268715008, 546325401769976582587561, 203541885180568005538811904, 89218786842877518275107415625

Offset: 0

Author

Alois P. Heinz, Aug 06 2014

Keywords

• nonn

Links

• Alois P. Heinz, Table of n, a(n) for n = 0..150

Crossrefs

Column k=10 of A245910.

Programs

Maple

with(combinat):
b:= proc(n, i) option remember; unapply(`if`(n=0 or i=1, x^n,
      expand(add((i-1)!^j*multinomial(n, n-i*j, i$j)/j!*
      x^(igcd(i, 10)*j)*b(n-i*j, i-1)(x), j=0..n/i))), x)
    end:
a:= n-> add(binomial(n-1, j-1)*n^(n-j)*b(j$2)(n), j=0..n):
seq(a(n), n=0..20);