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Search: id:A136584
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| A136584 |
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G.f. A(x) satisfies: 1+x = Sum_{n>=0} C(2^n,n) * x^n / A(x)^(2^n). |
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+0
1
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| 1, 1, 3, 31, 1327, 170211, 68333813, 89675072255, 397525147082217, 6103188627225900995, 331088233835064606501621, 64490029272314754165301653295, 45679131008965219349145151231118965
(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) satisfies: 1+x = Sum_{n>=0} log( (1 + 2^n*x)/A(x) )^n / n!.
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EXAMPLE
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G.f. A(x) = 1 + x + 3*x^2 + 31*x^3 + 1327*x^4 + 170211*x^5 + ...
1 + x = Sum_{n>=0} C(2^n,n) * x^n * A(x)^(-2^n) =
(1 - x - 2x^2 - 26x^3 - 1264x^4 - 167480x^5 - 67988870x^6 -...) +
.2x*(1 - 2x - 3x^2 - 48x^3 - 2472x^4 - 332328x^5 -...) +
...6x^2*(1 - 4x - 2x^2 - 84x^3 - 4743x^4 - 654480x^5 -...) +
.......56x^3*(1 - 8x + 12x^2 - 152x^3 - 8810x^4 -...) +
..........1820x^4*(1 - 16x + 88x^2 - 496x^3 - 15044x^4 -...) +
..............201376x^5*(1 - 32x + 432x^2 - 3808x^3 -...) +
..................74974368x^6*(1 - 64x + 1888x^2 +...) + ...
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PROGRAM
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(PARI) {a(n)=local(A=[1, 1]); if(n<0, 0, if(n==0, 1, for(i=0, n-1, A=concat(A, 0); A[ #A]=Vec(sum(n=0, #A-1, log((1+2^n*x)/Ser(A))^n/n!))[ #A]); A[n+1]))}
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CROSSREFS
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Cf. A014070 (C(2^n, n)).
Sequence in context: A022514 A094579 A029729 this_sequence A141153 A144906 A081789
Adjacent sequences: A136581 A136582 A136583 this_sequence A136585 A136586 A136587
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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 09 2008
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