OFFSET
0,2
LINKS
Amiram Eldar, Table of n, a(n) for n = 0..883
FORMULA
Sum_{k>=0} 1/a(k) = ( Pi+3*log(2) )/5 = 1.04420683905392583334286...
MATHEMATICA
Table[2^n * Binomial[3*n, n] * (3*n + 1), {n, 0, 20}] (* Amiram Eldar, May 04 2022 *)
PROG
(PARI) a(n)=2^n*binomial(3*n, n)*(3*n+1)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Benoit Cloitre, Aug 13 2002
STATUS
approved