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
KEYWORD
nonn
AUTHOR
EXTENSIONS
More terms from Sean A. Irvine, Oct 20 2019
STATUS
approved