OFFSET
0,3
COMMENTS
This sequence is related to sequence A001764.
FORMULA
Limit_{n->oo, n odd} A001764(n)/a(n) = 2/3.
a(n) = A001764(n) iff n is 1 or even.
G.f.: ((1 - 4F3(-1/6,1/6,1/3,2/3; 1/4,1/2,3/4; (729*x^2)/16)) / 3*x) + 4F3(1/6,1/3,2/3,5/6; 1/2,3/4,5/4; (729*x^2)/16).
E.g.f.: 4F5(1/6,1/3,2/3,5/6; 1/2,1/2,3/4,1,5/4; (729*x^2)/64) + x * 4F5(5/6,7/6,4/3,5/3; 5/4,3/2,3/2,7/4,2; (729*x^2)/64).
PROG
(PARI) f(n) = n\2*6-(-1)^n; \\ A007310
a(n) = my(x=f(n+1)); binomial(x, n)/x; \\ Michel Marcus, Nov 22 2023
CROSSREFS
KEYWORD
nonn
AUTHOR
Miko Labalan, Nov 21 2023
STATUS
approved