A187117 A diagonal of triangle A187115.

1, 6, 39, 318, 3242, 40348, 598083, 10337402, 204706486, 4577520108, 114208773268, 3147671423964, 95023271024164, 3119560618275648, 110684959354534001, 4221624141483353436, 172274971776090819870

Offset: 2

Author

Paul D. Hanna, Mar 08 2011

Keywords

• nonn

Comments

Definition of triangle: A187115(n,k) = [y^k] R_{n-1}(y+y^2) for k=2..n, n>2, where R_n(y) is the n-th row polynomial with R_2(y)=y^2.

Crossrefs

Cf. A187115, A135082, A187116, A187118, A187119.

Programs

PARI

{a(n)=local(Rn=y^2);for(m=2,n+2,Rn=subst(truncate(Rn),y,y+y^2+O(y^m)));polcoeff(Rn,n,y)}

Formula

Equals column 1 in the matrix cube of triangle A135080.