login
A361846
a(n) = Sum_{k=0..n} (-9)^k * binomial(-1/3,k) * binomial(n*k,n-k).
3
1, 3, 24, 243, 2973, 41676, 652662, 11228556, 209674050, 4211011422, 90309000630, 2056139084544, 49460437075896, 1251936022103679, 33228751234896060, 922028391785300940, 26676362307801924057, 802875670635086298600
OFFSET
0,2
LINKS
FORMULA
a(n) = [x^n] 1/(1 - 9*x*(1+x)^n)^(1/3).
PROG
(PARI) a(n) = sum(k=0, n, (-9)^k*binomial(-1/3, k)*binomial(n*k, n-k));
CROSSREFS
Main diagonal of A361839.
Sequence in context: A230325 A363416 A365154 * A365147 A080523 A203423
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Mar 27 2023
STATUS
approved