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Search: id:A096942
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| 5, 21, 55, 115, 210, 350, 546, 810, 1155, 1595, 2145, 2821, 3640, 4620, 5780, 7140, 8721, 10545, 12635, 15015, 17710, 20746, 24150, 27950, 32175, 36855, 42021, 47705, 53940, 60760, 68200, 76296, 85085, 94605, 104895, 115995, 127946, 140790, 154570
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OFFSET
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0,1
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COMMENT
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If Y is a 5-subset of an n-set X then, for n>=8, a(n-8) is the number of 4-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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a(n)= (n+20)*binomial(n+3, 3)/4 = 5*b(n)-4*b(n-1), with b(n):= A000332(n+4)=binomial(n+4, 4).
G.f.: (5-4*x)/(1-x)^5.
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CROSSREFS
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Fourth column: A096941; sixth column: A096943.
Adjacent sequences: A096939 A096940 A096941 this_sequence A096943 A096944 A096945
Sequence in context: A022268 A099979 A039659 this_sequence A122244 A033275 A059859
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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), Jul 16 2004
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