A034271 a(n) = f(n,n+4) where f is given in A034261.

0, 1, 15, 125, 814, 4641, 24388, 121380, 581400, 2707386, 12339569, 55304535, 244567050, 1069784625, 4637437560, 19951650840, 85290143760, 362608278750, 1534330716750, 6465583372794, 27147098904156, 113618646478106, 474177584413720, 1973918305023000, 8198353999348240

Offset: 0

Author

Clark Kimberling

Keywords

• nonn
• changed

Crossrefs

Cf. A034261.

Programs

Mathematica

a[n_] := Binomial[2*n + 4, n + 5]*(n^2 + 5*n + 1)/(n + 6); Array[a, 25, 0] (* Amiram Eldar, Sep 04 2025 *)

Formula

From Amiram Eldar, Sep 04 2025: (Start)

a(n) = binomial(2*n+4, n+5)*(n^2+5*n+1)/(n+6);

a(n) ~ 2^(2*n+4) * sqrt(n/Pi). (End)

Extensions

Corrected and extended by N. J. A. Sloane, Apr 21 2000