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Search: id:A016790
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| 4, 25, 64, 121, 196, 289, 400, 529, 676, 841, 1024, 1225, 1444, 1681, 1936, 2209, 2500, 2809, 3136, 3481, 3844, 4225, 4624, 5041, 5476, 5929, 6400, 6889, 7396, 7921, 8464, 9025, 9604, 10201, 10816, 11449
(list; graph; listen)
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OFFSET
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0,1
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COMMENT
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If Y is a fixed 2-subset of a (3n+1)-set X then a(n-1) is the number of 3-subsets of X intersecting Y. - Milan R. Janjic (agnus(AT)blic.net), Oct 21 2007
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LINKS
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Milan Janjic, Two Enumerative Functions
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FORMULA
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a(n) = A016958a(n)/4 [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Jun 30 2009]
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PROGRAM
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(Other) sage: [crt(4, n, 3, 5)^2/4 for n in xrange(4, 40)] # [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Jun 30 2009]
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CROSSREFS
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A016957, A016958 [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Jun 30 2009]
Sequence in context: A089767 A135784 A131069 this_sequence A065733 A077205 A125309
Adjacent sequences: A016787 A016788 A016789 this_sequence A016791 A016792 A016793
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KEYWORD
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nonn,easy
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com).
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