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A309678
G.f. A(x) satisfies: A(x) = A(x^4) / (1 - x)^2.
2
1, 2, 3, 4, 7, 10, 13, 16, 22, 28, 34, 40, 50, 60, 70, 80, 97, 114, 131, 148, 175, 202, 229, 256, 296, 336, 376, 416, 472, 528, 584, 640, 718, 796, 874, 952, 1058, 1164, 1270, 1376, 1516, 1656, 1796, 1936, 2116, 2296, 2476, 2656, 2886, 3116, 3346, 3576, 3866, 4156, 4446, 4736, 5096
OFFSET
0,2
FORMULA
G.f.: Product_{k>=0} 1/(1 - x^(4^k))^2.
MATHEMATICA
nmax = 56; A[_] = 1; Do[A[x_] = A[x^4]/(1 - x)^2 + O[x]^(nmax + 1) // Normal, nmax + 1]; CoefficientList[A[x], x]
nmax = 56; CoefficientList[Series[Product[1/(1 - x^(4^k))^2, {k, 0, Floor[Log[4, nmax]] + 1}], {x, 0, nmax}], x]
CROSSREFS
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, Aug 12 2019
STATUS
approved