Product_{n>=1} (1 + x^n)^(a(n)/n!) = 1 + arctanh(x).

A354276

Product_{n>=1} (1 + x^n)^(a(n)/n!) = 1 + arctanh(x).

Terms

    a(0) =1a(1) =0a(2) =2a(3) =-8a(4) =64a(5) =-304a(6) =3968a(7) =-43392a(8) =378880a(9) =-4002816a(10) =68247552a(11) =-995736576a(12) =15949529088a(13) =-238273241088

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