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Search: id:A134528
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| A134528 |
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G.f. A(x) satisfies: 1 = Sum_{n>=0} A(x)^(n+1)*x^n/2^(n*(n-1)/2) where A(x) = Sum_{n>=0} a(n)*x^n/2^(n*(n-1)/2). |
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+0
1
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| 1, -1, 3, -21, 319, -10193, 674047, -91369921, 25234490623, -14140806673665, 16031563354478591, -36691986271455923201, 169262051631703928107007, -1571807846118598776606101505, 29353752424684301883376834576383, -1101562988034649825668233119938625537
(list; graph; listen)
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OFFSET
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0,3
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FORMULA
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G.f.: A(x) = (1/x)*series_reversion[x*Sum_{n>=0} x^n/2^(n*(n-1)/2)].
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EXAMPLE
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A(x) = 1 - x + 3/2*x^2 - 21/8*x^3 + 319/64*x^4 - 10193/1024*x^5 +...
1 = A(x) + A(x)^2*x + A(x)^3*x^2/2 + A(x)^4*x^3/8 + A(x)^5*x^4/64 + ...
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PROGRAM
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(PARI) {a(n)=2^(n*(n+1)/2)*polcoeff((1/x)*serreverse(sum(k=1, n+1, x^k/2^(k*(k-1)/2))+O(x^(n+2))), n)}
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CROSSREFS
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Cf. A118410.
Adjacent sequences: A134525 A134526 A134527 this_sequence A134529 A134530 A134531
Sequence in context: A000681 A055555 A005329 this_sequence A118410 A125054 A113085
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KEYWORD
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sign
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AUTHOR
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Paul D. Hanna (pauldhanna(AT)juno.com), Nov 23 2007
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