A258958 Number of (n+2) X (n+2) 0..1 arrays with no 3 X 3 subblock diagonal sum 0 and no antidiagonal sum 3 and no row sum 0 or 3 and no column sum 0 or 3.

66, 344, 192, 312, 384, 694, 720, 1210, 1440, 2674, 2880, 4840, 5760, 10696, 11520, 19360, 23040, 42784, 46080, 77440, 92160, 171136, 184320, 309760, 368640, 684544, 737280, 1239040, 1474560, 2738176, 2949120, 4956160, 5898240, 10952704

Offset

1,1

Links

R. H. Hardin, Table of n, a(n) for n = 1..53

Formula

Empirical: a(n) = 4*a(n-4) for n>10.

Empirical g.f.: 2*x*(33 + 172*x + 96*x^2 + 156*x^3 + 60*x^4 - 341*x^5 - 24*x^6 - 19*x^7 - 48*x^8 - 51*x^9) / ((1 - 2*x^2)*(1 + 2*x^2)). - Colin Barker, Dec 23 2018

Example

Some solutions for n=4:
..1..0..1..0..1..0....1..0..1..0..1..0....1..1..0..1..0..1....0..1..0..1..0..0
..0..0..1..0..1..1....1..0..1..0..1..1....1..0..1..0..1..0....1..0..0..1..1..0
..1..1..0..1..0..0....0..1..0..1..0..0....0..0..1..0..1..0....0..1..1..0..0..1
..0..1..0..1..0..1....0..1..0..1..0..1....1..1..0..1..0..1....1..0..0..1..1..0
..1..0..1..0..1..0....1..0..1..0..1..1....0..1..0..1..0..1....0..1..1..0..0..1
..0..0..1..0..1..1....1..0..1..0..1..0....1..0..1..0..1..0....0..0..1..0..1..0

Crossrefs

Diagonal of A258966.

Sequence in context: A251055 A251048 A259292 * A120102 A244286 A223444

Adjacent sequences: A258955 A258956 A258957 * A258959 A258960 A258961

Keyword

nonn

Author

R. H. Hardin, Jun 15 2015

Status

approved