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A353912 Product_{n>=1} 1 / (1 - a(n)*x^n/n!) = 1 + tanh(x). 6

%I #6 May 11 2022 10:37:21

%S 1,-2,-2,-16,-24,64,-720,-23808,-35840,282368,-3628800,-75458560,

%T -479001600,5315078144,-82614884352,-8601835798528,-20922789888000,

%U 321288633450496,-6402373705728000,-309168395474436096,-2379913632645120000,46441359567137275904

%N Product_{n>=1} 1 / (1 - a(n)*x^n/n!) = 1 + tanh(x).

%t nn = 22; f[x_] := Product[1/(1 - a[n] x^n/n!), {n, 1, nn}]; sol = SolveAlways[0 == Series[f[x] - 1 - Tanh[x], {x, 0, nn}], x]; Table[a[n], {n, 1, nn}] /. sol // Flatten

%Y Cf. A155585, A353779, A353873, A353910, A353911.

%K sign

%O 1,2

%A _Ilya Gutkovskiy_, May 10 2022

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Last modified September 8 22:43 EDT 2024. Contains 375759 sequences. (Running on oeis4.)