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Search: id:A136652
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| A136652 |
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L.g.f.: A(x) = log( Sum_{n>=0} 2^[n(n-1)/2]*x^n ). |
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+0
2
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| 1, 3, 19, 223, 4771, 190023, 14441659, 2130394591, 616038609331, 351153716973303, 395928966997611499, 885010943452285951183, 3928049212346654960720611, 34658088824057172975437120103
(list; graph; listen)
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OFFSET
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1,2
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EXAMPLE
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L.g.f.: A(x) = x + 3*x^2/2 + 19*x^3/3 + 223*x^4/4 + 4771*x^5/5 +...
A(x) = log(1 + x + 2x^2 + 8x^3 + 64x^4 + 1024x^5 +...+ 2^(n(n-1)/2)*x^n +...).
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PROGRAM
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(PARI) a(n)=n*polcoeff(log(sum(k=0, n, 2^(k*(k-1)/2)*x^k +x*O(x^n))), n)
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CROSSREFS
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Cf. A136653, A136654.
Sequence in context: A005647 A001833 A001035 this_sequence A136504 A003111 A126444
Adjacent sequences: A136649 A136650 A136651 this_sequence A136653 A136654 A136655
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KEYWORD
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nonn
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AUTHOR
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Paul D. Hanna (pauldhanna(AT)juno.com), Jan 15 2008
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