A026958 a(n) = Sum_{k=0..n-2} T(n,k) * T(n,k+2), with T given by A026615.

1, 10, 69, 340, 1476, 6074, 24419, 97136, 384428, 1517422, 5981070, 23556746, 92743296, 365078146, 1437124303, 5657887016, 22279053380, 87749051950, 345704345066, 1362361338578, 5370436417996, 21176724230654, 83529562154498, 329573910914930, 1300752571946396

Offset: 2

Author

Clark Kimberling

Keywords

• nonn

Links

• G. C. Greubel, Table of n, a(n) for n = 2..1000

Crossrefs

Cf. A026615, A026616, A026617, A026618, A026619, A026620, A026621.

Cf. A026622, A026623, A026624, A026625, A026956, A026957, A026959.

Cf. A026960.

Programs

Magma

[n eq 2 select 1 else Binomial(2*n,n+2)*(49*n^4 -154*n^3 + 209*n^2 -200*n +108)/(24*Binomial(2*n,4)) -2*(n^2-2*n+2): n in [2..40]]; // G. C. Greubel, Jun 17 2024

Mathematica

Table[Binomial[2*n,n+2]*(49*n^4 -154*n^3 +209*n^2 -200*n +108)/(24* Binomial[2*n,4]) -2*(n^2-2*n+2) + Boole[n==2], {n,2,40}] (* G. C. Greubel, Jun 17 2024 *)

SageMath

[binomial(2*n,n+2)*(49*n^4 -154*n^3 +209*n^2 -200*n +108 )/(24*binomial(2*n,4)) -2*(n^2-2*n+2) +int(n==2) for n in range(2,41)] # G. C. Greubel, Jun 17 2024

Formula

a(n) = binomial(2*n, n+2)*(49*n^4 - 154*n^3 + 209*n^2 - 200*n + 108)/(24*binomial(2*n, 4)) -2*(n^2 - 2*n + 2) + [n=2]. - G. C. Greubel, Jun 17 2024

Extensions

More terms from Sean A. Irvine, Oct 20 2019