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Search: id:A039619
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| 1, 9, 107, 1650, 31594, 725592, 19471500, 598482000, 20742534576, 800575997760, 34059828307680, 1583808130195200, 79925022369273600, 4350478314951982080, 254086498336122950400, 15849890120755311667200
(list; graph; listen)
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OFFSET
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2,2
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COMMENT
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Explicit formula using partitions of n into 2 parts: cf. Knuth's paper for f(n,2), n >= 2, formula with f(k) as given above.
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REFERENCES
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D. E. Knuth, Convolution polynomials, The Mathematica J., 2.1 (1992) 67-78.
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FORMULA
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a(n) = sum(binomial(n-1, j-1)*f(j)*f(n-j), j=1..n-1) with f(k) := A006963(k+1) = (2*k+1)!/k!, k >= 1.
E.g.f.: ln((1-sqrt(1-4*x))/x/2)^2/2. - Vladeta Jovovic (vladeta(AT)Eunet.yu), May 02 2003
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CROSSREFS
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A006963, A038455.
Cf. A039646.
Adjacent sequences: A039616 A039617 A039618 this_sequence A039620 A039621 A039622
Sequence in context: A012485 A052503 A122569 this_sequence A080505 A104224 A099676
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KEYWORD
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nonn
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AUTHOR
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Wolfdieter Lang (wolfdieter.lang(AT)physik.uni-karlsruhe.de)
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