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Search: id:A122992
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| A122992 |
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G.f.: A(x) = Product_{n>=0} ( 1 + x*(1+x)^n )^( 1/2^(n+1) ). |
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+0
2
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| 1, 1, 1, 1, 0, -2, -5, -3, 27, 145, 382, -24, -6796, -44972, -167234, -105302, 4182671, 41042943, 232150003, 618910867, -4104725087, -76739338173, -670022786184, -3614373261686, -3033843119112, 208905541624840, 3094995814651910, 27593428414596086
(list; graph; listen)
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OFFSET
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0,6
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EXAMPLE
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A(x) = (1+x)^(1/2) * (1 + x*(1+x))^(1/4) * (1 + x*(1+x)^2)^(1/8) * (1 + x*(1+x)^3)^(1/16) * ...
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PROGRAM
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(PARI) {a(n)=round(polcoeff(prod(i=0, 6*n+10, (1+x*(1+x)^i +x*O(x^n))^(1/2^(i+1))), n))}
(PARI) {a(n)=local(A); if(n<0, 0, A=1+O(x); for(k=1, n, A=truncate(A)+x*O(x^k); A+=substvec(A, [x, y], [x*(1+x*y), y/(1+x*y+O(x^k))]) -A^2/(1+x)); subst(polcoeff(A, n), y, 1))} /* Michael Somos Oct 21 2006 */
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CROSSREFS
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Cf. A122993.
Adjacent sequences: A122989 A122990 A122991 this_sequence A122993 A122994 A122995
Sequence in context: A077216 A058357 A097754 this_sequence A051497 A109734 A077073
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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), Sep 23 2006
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