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A308986
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Expansion of Product_{k>=0} 1/(1 + 2*x^(2^k)).
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2
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1, -2, 2, -4, 10, -20, 36, -72, 154, -308, 596, -1192, 2420, -4840, 9608, -19216, 38586, -77172, 154036, -308072, 616740, -1233480, 2465768, -4931536, 9865492, -19730984, 39457128, -78914256, 157838120, -315676240, 631333264, -1262666528, 2525371642, -5050743284
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OFFSET
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0,2
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COMMENTS
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LINKS
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FORMULA
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a(0) = 1; a(n) = -Sum_{k=1..n} 2^A000120(k) * a(n-k).
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MATHEMATICA
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nmax = 33; CoefficientList[Series[Product[1/(1 + 2 x^(2^k)), {k, 0, Floor[Log[2, nmax]] + 1}], {x, 0, nmax}], x]
a[0] = 1; a[n_] := a[n] = -Sum[2^DigitCount[k, 2, 1] a[n - k], {k, 1, n}]; Table[a[n], {n, 0, 33}]
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CROSSREFS
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KEYWORD
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sign
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AUTHOR
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STATUS
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approved
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