A026962 a(n) = Sum_{k=0..n-1} T(n,k) * T(n,k+1), with T given by A026626.

1, 6, 24, 108, 406, 1572, 5961, 22788, 87209, 335010, 1290376, 4983162, 19286891, 74797176, 290586771, 1130716508, 4406049037, 17191077082, 67152699384, 262594530318, 1027851765350, 4026831276662, 15788979175102, 61954847930374, 243278117470476, 955907159445522

Offset

1,2

Links

G. C. Greubel, Table of n, a(n) for n = 1..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 *)
A262962[n_]:=Sum[T[n, k]*T[n, k+1], {k, 0, n-1}];
Table[A262962[n], {n, 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 A262962(n): return sum( T(n, k)*T(n, k+1) for k in range(n))
[A262962(n) for n in range(1, 41)] # G. C. Greubel, Jun 23 2024

Crossrefs

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

Cf. A026633, A026634, A026635, A026636, A026961, A026963, A026964.

Cf. A026965.

Sequence in context: A372225 A122740 A034432 * A026972 A075484 A122739

Adjacent sequences: A026959 A026960 A026961 * A026963 A026964 A026965

Keyword

nonn

Author

Clark Kimberling

Extensions

More terms from Sean A. Irvine, Oct 20 2019

Status

approved