A018803 Number of ways to color cells of an n X n square with 2 colors so that no subsquare of side > 1 has all corners same color.

1, 2, 14, 276, 10980, 781712, 58339148, 3066831440, 58170992144, 313031791856, 109957124552, 5020721992, 3980056, 1140264, 232228

Offset

0,2

Comments

There is no solution for a 15 X 15 (or larger) square. - Sean A. Irvine, Feb 13 2019

Links

Table of n, a(n) for n=0..14.

R. Bacher and S. Eliahou, Extremal binary matrices without constant 2-squares (see p. 11).

R. Bacher and S. Eliahou, Extremal binary matrices without constant 2-squares, The Electronic Journal of Combinatorics, Open Journal Systems, 2010, 1 (1), pp.77-100. See p. 87.

Crossrefs

Main diagonal of A255256.

Sequence in context: A015197 A156910 A279117 * A217474 A132695 A015015

Adjacent sequences: A018800 A018801 A018802 * A018804 A018805 A018806

Keyword

nonn,fini,full

Author

David W. Wilson

Extensions

a(0)=1 from Alois P. Heinz, Feb 19 2015

More terms from Bacher and Eliahou paper added by Sean A. Irvine, Feb 13 2019

Status

approved