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Search: id:A095819
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| 4, 37, 190, 715, 2200, 5863, 14014, 30745, 62920, 121550, 223652, 394706, 671840, 1107890, 1776500, 2778446, 4249388, 6369275, 9373650, 13567125, 19339320, 27183585, 37718850, 51714975, 70122000, 94103724, 125076072, 164750740
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OFFSET
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0,1
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COMMENT
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If Y is a 4-subset of an n-set X then, for n>=12, a(n-12) is the number of 9-subsets of X having at most one element in common with Y. - Milan R. Janjic (agnus(AT)blic.net), Dec 08 2007
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FORMULA
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G.f.: (4-3*x)/(1-x)^10.
a(n) = 4*b(n)-3*b(n-1) =(n+36)*binomial(n+8, 8)/9, with b(n):=binomial(n+9, 9)=A000582(n+9, 9).
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CROSSREFS
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Adjacent sequences: A095816 A095817 A095818 this_sequence A095820 A095821 A095822
Sequence in context: A031189 A045555 A063418 this_sequence A025542 A133462 A123762
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KEYWORD
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nonn,easy
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AUTHOR
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Wolfdieter Lang (wolfdieter.lang_AT_physik_DOT_uni-karlsruhe_DOT_de), Jun 11 2004
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