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A027378
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Expansion of (1+x^2-x^3)/(1-x)^4.
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0
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1, 4, 11, 23, 41, 66, 99, 141, 193, 256, 331, 419, 521, 638, 771, 921, 1089, 1276, 1483, 1711, 1961, 2234, 2531, 2853, 3201, 3576, 3979, 4411, 4873, 5366, 5891, 6449, 7041, 7668, 8331, 9031, 9769, 10546
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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COMMENTS
| If Y is a 3-subset of an n-set X then, for n>=4, a(n-4) is the number of (n-3)-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-3)=binomial(n,3)-3*n+9, n=4,5,6,.... - Milan R. Janjic (agnus(AT)blic.net), Dec 28 2007
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CROSSREFS
| Sequence in context: A008071 A008172 A009907 * A092498 A131177 A019298
Adjacent sequences: A027375 A027376 A027377 * A027379 A027380 A027381
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KEYWORD
| nonn
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com).
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