OFFSET
0,3
COMMENTS
Diagonal sums of A100100.
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..1000
FORMULA
a(n) = Sum_{k=0..floor(n/2)} binomial(2*n-3*k-1, n-2*k).
MATHEMATICA
A100217[n_]:= Sum[Binomial[2*n-3*k-1, n-2*k], {k, 0, Floor[n/2]}];
Table[A100217[n], {n, 0, 40}] (* G. C. Greubel, Mar 28 2024 *)
PROG
(Magma) [(&+[Binomial(2*n-3*k-1, n-2*k): k in [0..Floor(n/2)]]): n in [0..40]]; // G. C. Greubel, Mar 28 2024
(SageMath) [sum(binomial(2*n-3*k-1, n-2*k) for k in range(1+n//2)) for n in range(41)] # G. C. Greubel, Mar 28 2024
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Paul Barry, Nov 08 2004
STATUS
approved