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A135068
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a(n) = [x^(2^n+n-1)] (x + x^2 + x^4 + x^8 + ... + x^2^n)^n for n>=1.
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4
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1, 2, 6, 16, 90, 636, 5712, 34336, 537282, 5941780, 99729146, 1049982792, 23200347040, 293841338896, 5712436923000, 68827002466176, 2844850573581890, 53069160498788772, 1545326270301621838, 26021954987946879560, 1020860369624228471394, 19905401189634441143740
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OFFSET
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1,2
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LINKS
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FORMULA
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MATHEMATICA
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f[x_, n_] := (Sum[x^(2^k), {k, 0, n}])^n; Table[Coefficient[f[x, n], x^(2^n + n - 1)] , {n, 1, 20}] (* G. C. Greubel, Sep 22 2016 *)
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PROG
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(PARI) a(n)=if(n<1, 0, polcoeff(sum(j=0, n, x^(2^j)+O(x^(2^n+n)))^n, 2^n+n-1))
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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