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A055798
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T(2n+5,n), array T as in A055794.
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0
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1, 7, 29, 93, 255, 627, 1419, 3003, 6006, 11440, 20878, 36686, 62322, 102714, 164730, 257754, 394383, 591261, 870067, 1258675, 1792505, 2516085, 3484845, 4767165, 6446700, 8625006, 11424492, 14991724, 19501108, 25158980, 32208132, 40932804, 51664173
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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COMMENTS
| If Y is a 2-subset of an n-set X then, for n>=8, a(n-8) is the number of 8-subsets of X which have no exactly one element in common with Y. - Milan R. Janjic (agnus(AT)blic.net), Dec 28 2007
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FORMULA
| a(n-8)=binomial(n,8)-2*binomial(n-2,7), n=8,9,10,.... - Milan R. Janjic (agnus(AT)blic.net), Dec 28 2007
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MATHEMATICA
| CoefficientList[Series[(-2*(z - 1)*z - 1)/(z - 1)^9, {z, 0, 100}], z] (* From Vladimir Joseph Stephan Orlovsky, Jul 16 2011 *)
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CROSSREFS
| Sequence in context: A166189 A001779 A053295 * A002664 A042609 A002941
Adjacent sequences: A055795 A055796 A055797 * A055799 A055800 A055801
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KEYWORD
| nonn
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AUTHOR
| Clark Kimberling (ck6(AT)evansville.edu), May 28 2000
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