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Search: id:A120625
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| A120625 |
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Numbers n such that the n-th Catalan number C(2n,n)/(n+1) is divisible by 3n(n+1). |
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+0
2
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| 15, 20, 42, 77, 88, 104, 126, 140, 153, 156, 170, 187, 190, 204, 209, 210, 220, 228, 231, 238, 240, 266, 299, 308, 312, 322, 368, 420, 429, 435, 440, 442, 450, 460, 464, 468, 476, 483, 493, 496, 510, 527, 551, 558, 561, 580, 589, 600, 609, 620, 624, 651, 665
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OFFSET
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1,1
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COMMENT
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Equivalently, numbers n such that the n-th central binomial coefficient C(2n,n) is divisible by 3n(n+1). - Joel B. Lewis (jblewis(AT)post.harvard.edu), Jan 07 2008
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MATHEMATICA
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fQ[n_] := fQ[n_] := IntegerQ[ Binomial[2n, n]/(3n(n + 1))]; Select[ Range@681, fQ@# &]
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CROSSREFS
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Subset of A104847, Cf. A120623.
Adjacent sequences: A120622 A120623 A120624 this_sequence A120626 A120627 A120628
Sequence in context: A065148 A093028 A105506 this_sequence A038352 A043125 A043905
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KEYWORD
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nonn
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AUTHOR
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Robert G. Wilson v (rgwv(AT)rgwv.com), Jun 19 2006
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