A292692 a(n) = A258220(2n,n).

1, 6, 217, 13997, 1283817, 151778430, 21902350480, 3726598826676, 729894290301789, 161683308639785288, 39960246577221138239, 10900687898284398341055, 3253179971490906621196740, 1054372896576358319473872858, 368810384314446516250937494104

Offset

0,2

Links

Vaclav Kotesovec, Table of n, a(n) for n = 0..290 (terms 0..200 from Alois P. Heinz)

Formula

a(n) ~ c * d^n * n! / sqrt(n), where d = 25.81959672662517201... and c = 0.28310309251343879... - Vaclav Kotesovec, Dec 01 2017

Conjecture: d = (51*sqrt(17) - 107)/4. - Vaclav Kotesovec, Mar 17 2024

Crossrefs

Cf. A258220.

Sequence in context: A229869 A234610 A041623 * A015477 A331477 A144658

Adjacent sequences: A292689 A292690 A292691 * A292693 A292694 A292695

Keyword

nonn

Author

Alois P. Heinz, Sep 20 2017

Status

approved