|
|
A024720
|
|
a(n) = (1/4)*(3 + Sum_{k=0..n} C(4k,k)).
|
|
0
|
|
|
1, 2, 9, 64, 519, 4395, 38044, 334054, 2963629, 26499449, 238414581, 2155749364, 19572882981, 178326272881, 1629509263831, 14928031562011, 137059765831906, 1260847661188318, 11618870102584178, 107234108018545278
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
0,2
|
|
LINKS
|
|
|
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
|
|
|
STATUS
|
approved
|
|
|
|