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%I M4998 #20 Dec 26 2021 14:09:30
%S 16,23,32,43,52,62,75,87,101,118
%N Zarankiewicz's problem k_4(n).
%C a(n) is the least k such that every n X n {0,1}-matrix with k ones contains an all ones 4 X 4 submatrix. - _Sean A. Irvine_, May 17 2017
%D N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
%H R. K. Guy, <a href="/A001197/a001197.pdf">A problem of Zarankiewicz</a>, Research Paper No. 12, Dept. of Math., Univ. Calgary, Jan. 1967. [Annotated and scanned copy, with permission]
%H R. K. Guy, <a href="http://dx.doi.org/10.1007/BFb0060112">A many-facetted problem of Zarankiewicz</a>, Lect. Notes Math. 110 (1969), 129-148.
%F a(n) = n^2 - A347474(n). - _Andrew Howroyd_, Dec 26 2021
%Y Cf. A001197, A001198, A006626, A339635, A347474.
%K nonn,hard,more
%O 4,1
%A _N. J. A. Sloane_
%E a(9)-a(13) from _Andrew Howroyd_, Dec 26 2021