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A309733 Expansion of Product_{k>=1} 1/(1 - x^k/(1 - x^(2*k))). 1

%I

%S 1,1,2,4,7,12,22,36,62,104,174,286,478,780,1284,2100,3433,5586,9114,

%T 14798,24064,39050,63376,102726,166584,269835,437190,707964,1146480,

%U 1855966,3004748,4863306,7871798,12739576,20617652,33364524,53992834,87369548,141379728,228769842

%N Expansion of Product_{k>=1} 1/(1 - x^k/(1 - x^(2*k))).

%F a(n) ~ phi^(n+1), where phi = A001622 = (1+sqrt(5))/2 is the golden ratio. - _Vaclav Kotesovec_, Sep 22 2019

%t nmax = 40; CoefficientList[Series[Product[1/(1 - x^k/(1 - x^(2*k))), {k, 1, nmax}], {x, 0, nmax}], x] (* _Vaclav Kotesovec_, Sep 22 2019 *)

%o (PARI) N=66; x='x+O('x^N); Vec(1/prod(k=1, N, 1-x^k/(1-x^(2*k))))

%Y Cf. A006951, A055922, A162891.

%K nonn

%O 0,3

%A _Seiichi Manyama_, Sep 22 2019

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Last modified July 11 18:01 EDT 2020. Contains 335652 sequences. (Running on oeis4.)