A006626 - OEIS

%I M5071 #18 Dec 26 2021 18:26:15

%S 19,27,37,46,56,68,80,94,109

%N Zarankiewicz's problem k_4(n,n+1).

%C a(n) is the least k such that every n X (n+1) {0,1}-matrix with k ones contains an all ones 4 X 4 submatrix. - _Sean A. Irvine_, May 18 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="http://dx.doi.org/10.1007/BFb0060112">A many-facetted problem of Zarankiewicz</a>, Lect. Notes Math. 110 (1969), 129-148.

%Y Cf. A006616 (k_4(n)), A006620 (k_2(n,n+1)), A006621 (k_3(n,n+1)).

%K nonn,more

%O 4,1

%A _N. J. A. Sloane_

%E a(9)-a(12) from _Andrew Howroyd_, Dec 26 2021