OFFSET
0,2
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..300
Stefan Forcey, Aaron Lauve and Frank Sottile, Cofree compositions of coalgebras, Annals of Combinatorics 17 (1) pp. 105-130 March, 2013.
FORMULA
a(n) ~ n! * (1 + 2/n + 8/n^2 + 44/n^3 + 288/n^4 + 2148/n^5 + 17816/n^6 + 161852/n^7 + 1594280/n^8 + 16911940/n^9 + 192361656/n^10), for coefficients see A260879. - Vaclav Kotesovec, Aug 02 2015
MAPLE
a:= proc(n) option remember;
`if`(n=0, 1, n! +add(a(i)*a(n-1-i), i=0..n-1))
end:
seq(a(n), n=0..30); # Alois P. Heinz, Oct 10 2013
MATHEMATICA
a[0] = 1; a[n_] := a[n] = n! + Sum[a[i]*a[n-1-i], {i, 0, n-1}]; Table[a[n], {n, 0, 30}] (* Jean-François Alcover, Mar 07 2014 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Oct 05 2013
STATUS
approved