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%I #7 Mar 30 2012 18:35:07
%S 0,0,0,0,0,0,1,3,8,20,48,136,344,788,1775,3947,9373,21533,48327,
%T 104676,224997,496490,1082575,2334984,4997364,10532236,22568064,
%U 48062489,101796210,214545469,450146443,946329292,1980769346
%N Number of subsets of { 1, ..., n } containing an A.P. of length 6.
%K nonn
%O 0,8
%A _David W. Wilson_