%I A066369
%S A066369 1,2,4,8,15,29,56,103,192,364,668,1222,2233,3987,7138,12903,22601,
%T A066369 40200,71583,125184,218693,386543,670989,1164385,2021678,3462265,
%U A066369 5930954,10189081,17266616,29654738,50912618
%N A066369 Number of subsets of {1, ..., n} with no four terms in arithmetic progression.
%e A066369 a(5) = 29 because there are 32 subsets and three of them contain four 
               terms in arithmetic progression: {1, 2, 3, 4}, {2, 3, 4, 5} and {1, 
               2, 3, 4, 5}.
%Y A066369 Cf. A051013.
%Y A066369 Sequence in context: A036621 A001383 A108564 this_sequence A000078 A034338 
               A166861
%Y A066369 Adjacent sequences: A066366 A066367 A066368 this_sequence A066370 A066371 
               A066372
%K A066369 nonn
%O A066369 0,2
%A A066369 Jan Kristian Haugland (jankrihau(AT)hotmail.com), Dec 22 2001