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Search: id:A141153
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| A141153 |
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G.f.: A(x) = Sum_{n>=1} a(n-1)*x^(2*n)/(2*n) = log( Sum_{n>=0} a(n)*x^(2*n)/(n!*2^n) ). |
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+0 1
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| 1, 1, 3, 31, 1609, 626097, 2407996027, 110977327013551, 71594581089754557777, 738994182797188307880872353, 137301106425308220881681919632979379, 510195974626378486585193070538567102152265599
(list; graph; listen)
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OFFSET
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2,3
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FORMULA
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a(n+1) = n!*Sum_{k=0..n} 2^(n-k)/k!*a(k)*a(n-k), (offset 0). - Vladeta Jovovic (vladeta(AT)Eunet.yu), Jul 08 2008
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EXAMPLE
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G.f.: A(x) = x^2/2 + x^4/4 + 3*x^6/6 + 31*x^8/8 + 1609*x^10/10 + 626097*x^12/12 +...
exp(A(x)) = 1 + x^2/2 + 3*x^4/8 + 31*x^6/48 + 1609*x^8/384 + 626097*x^10/3840 +...
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PROGRAM
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(PARI) {a(n)=if(n==0, 1, n!*2^n*polcoeff(exp(sum(k=0, n-1, a(k)*x^(2*k+2)/(2*k+2))+O(x^(2*n+2))), 2*n))}
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CROSSREFS
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Adjacent sequences: A141150 A141151 A141152 this_sequence A141154 A141155 A141156
Sequence in context: A094579 A029729 A136584 this_sequence A081789 A066976 A048562
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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), Jun 11 2008
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