A245502 Number of endofunctions f on [n] such that f^6(i) = f(i) for all i in [n].

1, 1, 3, 10, 41, 220, 1921, 25474, 384113, 5785192, 85295105, 1244587246, 18399553801, 286188407116, 4920039471089, 96938148715090, 2172951409994081, 53076309208887760, 1351935357372173953, 35000099470802409814, 914038174404012874745, 24209598764577808155316

Offset

0,3

Links

Alois P. Heinz, Table of n, a(n) for n = 0..200

Formula

E.g.f.: exp(x*exp(x)+x^5*exp(x)^5/5).

Maple

egf:= exp(x*exp(x)+x^5*exp(x)^5/5):
a:= n-> n!*coeff(series(egf, x, n+1), x, n):
seq(a(n), n=0..25);

Crossrefs

Column k=6 of A245501.

Sequence in context: A030954 A084786 A156170 * A009329 A009364 A308951

Adjacent sequences: A245499 A245500 A245501 * A245503 A245504 A245505

Keyword

nonn

Author

Alois P. Heinz, Jul 24 2014

Status

approved