A108995 a(n) = A108994(n)*2/(n+2) for n>=0.

1, 2, 9, 72, 890, 15456, 352807, 10093728, 349534881, 14270091790, 672991000968, 36076060520556, 2169580363847949, 144810568283675126, 10631141835083823945, 851921010801706760672, 74031550751810889131475

Offset

0,2

Comments

a(n) is divisible by (n+1). A108994 is the third diagonal of triangle A108990, in which the g.f. of row n, R_n(x), satisfies: [x^k] R_{n+1}(x) = [x^k] (1 + x*R_n(x))^(n+1) for k=0..n+1.

Links

Table of n, a(n) for n=0..16.

Formula

a(n) = A108990(n+2, n)*2/(n+2) for n>=0.

Prog

(PARI) {a(n)=local(F=1); for(m=1, n+2, F=(1+x*F+x*O(x^n))^m); polcoeff(F, n)*2/(n+2)}

Crossrefs

Cf. A108990, A108991, A108992, A108993, A108994, A108996.

Sequence in context: A038035 A133984 A208898 * A184358 A132843 A346648

Adjacent sequences: A108992 A108993 A108994 * A108996 A108997 A108998

Keyword

nonn

Author

Paul D. Hanna, Jun 15 2005

Status

approved