A026132 a(n) = A026120(2n,n+1).

2, 10, 59, 336, 1922, 11033, 63609, 368197, 2138940, 12464893, 72842371, 426718241, 2505168510, 14735555475, 86824155165, 512368756524, 3027798553604, 17914997330328, 106121302605938, 629276226971340, 3735039117674430, 22188639701574873, 131922332486379081, 784931523363580176

Offset

1,1

Links

Table of n, a(n) for n=1..24.

Formula

a(n) ~ sqrt(15509*sqrt(13) + 30577) * (70 + 26*sqrt(13))^n / (2^(3/2) * 13^(1/4) * sqrt(Pi*n) * 3^(3*n + 7/2)). - Vaclav Kotesovec, Sep 19 2019

Mathematica

Table[Binomial[2*n, n] * ((2*n + 1)*(Hypergeometric2F1[-1/2 - n/2, -n/2, 2 + n, 4]/(n + 1)) + Hypergeometric2F1[1/2 - n/2, 1 - n/2, 2 + n, 4]/2 - 2*Hypergeometric2F1[1/2 - n/2, -n/2, 2 + n, 4]), {n, 1, 20}] (* Vaclav Kotesovec, Sep 19 2019 *)

Crossrefs

Cf. A026120, A026128, A026131.

Sequence in context: A112369 A218944 A124964 * A226996 A370247 A370273

Adjacent sequences: A026129 A026130 A026131 * A026133 A026134 A026135

Keyword

nonn

Author

Clark Kimberling

Extensions

More terms and title corrected by Sean A. Irvine, Sep 17 2019

Name corrected by Sean A. Irvine, Jan 12 2025

Status

approved