%I
%S 1,2,5,8,10,12,17,22,27,30,33,36,43,50,57,64,68,72,76,80,89,98,107,
%T 116,125
%N a(m^2) = m^3; a(m^2+k) = m^3 + km, 0 <= k <= m; a(m(m+1)) = (m+1)m^2; a(m(m+1)+k) = (m+1)m^2 + k(2m+1), 0 <= k <= m+1; a((m+1)^2) = (m+1)^3.
%C A lower bound on A121231(n), the maximal number of 1's in any (0,1)matrix M such that M^2 is also a (0,1)matrix.
%C For example, for m^2 x m^2 matrices one can obtain a(m^2) = m^3 using m^2 m x m matrices with one row of m of 1's and (m1) rows of m of 0's.
%K nonn
%O 1,2
%A _Dan Dima_, Aug 24 2006
%E Edited by R. J. Mathar, Oct 01 2008
