A026963 a(n) = Sum_{k=0..n-2} T(n,k) * T(n,k+2), with T given by A026626.

1, 8, 52, 224, 987, 3980, 16057, 63732, 252424, 996332, 3927977, 15471622, 60915547, 239794516, 943946193, 3716205884, 14632901696, 57631689776, 227042423404, 894698122022, 3526753844436, 13906101471344, 54848887043366, 216402159510134, 854053133294062, 3371593602442500

Offset

2,2

Links

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

Mathematica

T[n_, k_]:= T[n, k]= If[k==0 || k==n, 1, If[k==1 || k==n-1, Floor[3*n/2], T[n-1, k-1] +T[n-1, k]]]; (* T = A026626 *)
A262963[n_]:= Sum[T[n, k]*T[n, k+2], {k, 0, n-2}];
Table[A262963[n], {n, 2, 40}] (* G. C. Greubel, Jun 23 2024 *)

Prog

(SageMath)
@CachedFunction
def T(n, k): # T = A026626
    if (k==0 or k==n): return 1
    elif (k==1 or k==n-1): return int(3*n//2)
    else: return T(n-1, k-1) + T(n-1, k)
def A262963(n): return sum( T(n, k)*T(n, k+2) for k in range(n-1))
[A262963(n) for n in range(2, 41)] # G. C. Greubel, Jun 23 2024

Crossrefs

Cf. A026626, A026627, A026628, A026629, A026630, A026631, A026632.

Cf. A026633, A026634, A026635, A026636, A026961, A026962, A026964.

Cf. A026965.

Sequence in context: A303012 A024179 A302816 * A026973 A244718 A303509

Adjacent sequences: A026960 A026961 A026962 * A026964 A026965 A026966

Keyword

nonn

Author

Clark Kimberling

Extensions

More terms from Sean A. Irvine, Oct 20 2019

Status

approved