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Search: id:A129840
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| A129840 |
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a(n) = n! * sum{k=1 to n} binomial(2n+1,k)/k. |
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+0
1
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| 3, 20, 175, 2076, 32208, 626028, 14688924, 404166432, 12756813408, 454171720320, 18000130993920, 785833199683200, 37465916611881600, 1936722997186387200, 107888448215162361600, 6442944965583133593600, 410602312459198056960000
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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a(n) also equals (1/2)sum{k=1 to n} (k+n)! ((k-1)!4^k/(2k)! + 1/(k!k)).
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LINKS
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Leroy Quet, Home Page (listed in lieu of email address)
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MAPLE
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a:=n->n!*sum(binomial(2*n+1, k)/k, k=1..n): seq(a(n), n=1..20); - Emeric Deutsch (deutsch(AT)duke.poly.edu), May 27 2007
A129840 := proc(n) n!*add(binomial(2*n+1, k)/k, k=1..n) ; end: for n from 1 to 20 do printf("%d, ", A129840(n)) ; od ; - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Jun 08 2007
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MATHEMATICA
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Table[n!*Sum[Binomial[2n + 1, k]/k, {k, 1, n}], {n, 1, 25}] - Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), May 24 2007
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CROSSREFS
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Sequence in context: A051643 A154644 A000891 this_sequence A085390 A065980 A073767
Adjacent sequences: A129837 A129838 A129839 this_sequence A129841 A129842 A129843
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KEYWORD
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nonn
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AUTHOR
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Leroy Quet May 22 2007
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EXTENSIONS
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More terms from R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Stefan Steinerberger (stefan.steinerberger(AT)gmail.com) and Emeric Deutsch (deutsch(AT)duke.poly.edu), May 24 2007
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