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%I
%S 1,4,11,23,41,66,99,141,193,256,331,419,521,638,771,921,1089,1276,
%T 1483,1711,1961,2234,2531,2853,3201,3576,3979,4411,4873,5366,5891,
%U 6449,7041,7668,8331,9031,9769,10546
%N Expansion of (1+x^2-x^3)/(1-x)^4.
%C 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
%F a(n-3)=binomial(n,3)-3*n+9, n=4,5,6,.... - _Milan Janjic_, Dec 28 2007
%K nonn
%O 0,2
%A _N. J. A. Sloane_.
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