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A027378 Expansion of (1+x^2-x^3)/(1-x)^4. 0
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; text; internal format)
OFFSET

0,2

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 Janjic, Dec 28 2007

LINKS

Table of n, a(n) for n=0..37.

Index entries for linear recurrences with constant coefficients, signature (4,-6,4,-1).

FORMULA

a(n-3)=binomial(n,3)-3*n+9, n=4,5,6,.... - Milan Janjic, Dec 28 2007

CROSSREFS

Sequence in context: A009907 A301159 A298023 * A131177 A092498 A301165

Adjacent sequences:  A027375 A027376 A027377 * A027379 A027380 A027381

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane.

STATUS

approved

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Last modified October 19 05:01 EDT 2018. Contains 316336 sequences. (Running on oeis4.)