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A371825
a(n) = Sum_{k=0..n} n^k * binomial(2*n,n-k).
2
1, 3, 18, 146, 1510, 19302, 296520, 5339924, 110447046, 2581169510, 67274981356, 1934941601628, 60878718397276, 2080009638726684, 76694241037743300, 3035502492679964520, 128364744764608411718, 5776084128332328033798, 275565308510875579650348
OFFSET
0,2
FORMULA
a(n) = [x^n] 1/((1-(n+1)*x) * (1-x)^n).
a(n) ~ exp(2) * n^n. - Vaclav Kotesovec, Apr 07 2024
PROG
(PARI) a(n) = sum(k=0, n, n^k*binomial(2*n, n-k));
CROSSREFS
Sequence in context: A177383 A074525 A118331 * A240921 A373771 A221961
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Apr 07 2024
STATUS
approved