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%I M4681 #15 May 18 2017 09:58:16
%S 10,15,20,25,32,37,43,51
%N Zarankiewicz's problem.
%C a(n) is the least k such that every n X (n-1) {0,1}-matrix with k ones contains an all ones 2 X 3 submatrix. - _Sean A. Irvine_, May 18 2017
%D R. K. Guy, A many-facetted problem of Zarankiewicz, Lect. Notes Math. 110 (1969), 129-148.
%D N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
%K nonn,more
%O 4,1
%A _N. J. A. Sloane_.