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Search: id:A073179
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| A073179 |
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a(n) = n!^2 times coefficient of x^n in Sum_{k>=0} x^k/k!^2/4^k*((2-x)/(1-x))^(2*k). |
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+0
2
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| 1, 1, 5, 64, 1417, 47801, 2278981, 145735360, 12026529089, 1243307884537, 157278532956301, 23885127975415136, 4286460830620175065, 897058398619374567889, 216462065577670278012557
(list; graph; listen)
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OFFSET
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0,3
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REFERENCES
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R. P. Stanley, Enumerative Combinatorics, Cambridge, Vol. 2, 1999; see Problem 5.65(b).
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FORMULA
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Sum_{k>=0} x^k/k!^2/4^k*((2-x)/(1-x))^(2*k) = Sum_{n>=0} a(n)*x^n/n!^2. - Vladeta Jovovic (vladeta(AT)eunet.rs), Aug 01 2006
BesselI(0,(2-x)/(1-x)*sqrt(x)) = Sum_{n>=0} a(n)*x^n/n!^2. - Vladeta Jovovic (vladeta(AT)eunet.rs), Jun 20 2007
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PROGRAM
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(PARI) {a(n)=if(n<0, 0, n!^2*polcoeff(sum(k=0, n, x^k/k!^2/4^k* ((2-x)/(1-x))^(2*k), x*O(x^n)), n))}
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CROSSREFS
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Cf. A049088.
Sequence in context: A004193 A027667 A054937 this_sequence A061684 A061698 A126955
Adjacent sequences: A073176 A073177 A073178 this_sequence A073180 A073181 A073182
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KEYWORD
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nonn
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AUTHOR
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Michael Somos, Jul 19 2002
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