OFFSET
0,2
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..1000
FORMULA
G.f.: g/((1-4*x*g^3) * (1-x*g)) where g = 1+x*g^4 is the g.f. of A002293.
MATHEMATICA
Table[Sum[Binomial[n+3*k+1, k], {k, 0, n}], {n, 0, 20}] (* Vincenzo Librandi, Nov 06 2025 *)
PROG
(PARI) a(n) = sum(k=0, n, binomial(n+3*k+1, k));
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Nov 04 2025
STATUS
approved