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Expansion of Product_{n>=1} ((1 - (4*x)^n)/(1 + (4*x)^n))^(1/4).
3

%I #9 Apr 23 2018 18:51:57

%S 1,-2,-6,-28,-26,-156,-476,968,11526,-16172,139724,791928,1315548,

%T 12772840,31004424,-105335920,1058225606,2239259700,-3700870212,

%U 29301955992,-4944685836,-526686535112,1134044530040,4057865621232,-13063873857124,-113573062924024

%N Expansion of Product_{n>=1} ((1 - (4*x)^n)/(1 + (4*x)^n))^(1/4).

%o (PARI) N=66; x='x+O('x^N); Vec(prod(k=1, N, ((1-(4*x)^k)/(1+(4*x)^k))^(1/4)))

%Y Expansion of Product_{n>=1} ((1 + (2^b*x)^n)/(1 - (2^b)*x^n))^(1/(2^b)): A002448 (b=0), A303306 (b=1), this sequence (b=2), A303395 (b=3).

%Y Cf. A303361.

%K sign

%O 0,2

%A _Seiichi Manyama_, Apr 23 2018