OFFSET
0,1
LINKS
Robert Israel, Table of n, a(n) for n = 0..1652
FORMULA
a(n) = n*4^(n+1)+binomial(2*n+3, n+1).
G.f.: c(x)*(4-c(x))/(1-4*x)^2, where c(x) = g.f. for Catalan numbers A000108.
(160+64*n)*a(n) - (160+48*n)*a(n+1) + (50+12*n)*a(n+2) - (5+n)*a(n+3)=0. - Robert Israel, May 22 2019
MAPLE
seq(n*4^(n+1)+binomial(2*n+3, n+1), n=0..30); # Robert Israel, May 22 2019
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
STATUS
approved