A121294 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.

1, 2, 5, 8, 10, 12, 17, 22, 27, 30, 33, 36, 43, 50, 57, 64, 68, 72, 76, 80, 89, 98, 107, 116, 125

Offset

1,2

Comments

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.

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 (m-1) rows of m of 0's.

Links

Table of n, a(n) for n=1..25.

Crossrefs

Sequence in context: A294127 A166955 A286808 * A039770 A236019 A247426

Adjacent sequences: A121291 A121292 A121293 * A121295 A121296 A121297

Keyword

nonn

Author

Dan Dima, Aug 24 2006

Extensions

Edited by R. J. Mathar, Oct 01 2008

Status

approved