OFFSET
0,2
FORMULA
G.f.: (2*g-3)*g^4/((3*g-4)*(1-g+g^4)) where g = 1+x*g^4 is the g.f. of A002293. - Mark van Hoeij, Nov 11 2011
PROG
(PARI) a(n) = (3+sum(k=0, n, binomial(4*k, k)))/4; \\ Michel Marcus, May 10 2020
CROSSREFS
KEYWORD
nonn
AUTHOR
EXTENSIONS
More terms from James A. Sellers, May 01 2000
STATUS
approved