A270598 E.g.f.: Product_{k>0} (1 + tanh(x^k/k)).

1, 1, 1, 3, 14, 70, 364, 2548, 21104, 189936, 1830968, 20140648, 241712272, 3142259536, 43472528384, 652087925760, 10396900456448, 176747307759616, 3162885135453952, 60094817573625088, 1198006583353972736, 25158138250433427456, 551506339507727783936

Offset: 0

Author

Vaclav Kotesovec, Mar 20 2016

Keywords

• nonn

Links

• Vaclav Kotesovec, Table of n, a(n) for n = 0..448

Crossrefs

Cf. A130263, A130268, A218504, A270597.

Programs

Mathematica

nn=25; Range[0, nn]! * CoefficientList[Series[Product[1+Tanh[x^k/k], {k, 1, nn}], {x, 0, nn}], x]

Formula

E.g.f.: Product_{k>0} exp(x^k/k)/cosh(x^k/k).

a(n) ~ c * n!, where c = 1/A249673 = 1/Product_{k>=1} cosh(1/k) = 0.472485841489...