A258965 Number of (n+2) X (7+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.

2040, 1228, 456, 662, 552, 788, 720, 1046, 1080, 1570, 1800, 2618, 3240, 4714, 6120, 8906, 11880, 17290, 23400, 34058, 46440, 67594, 92520, 134666, 184680, 268810, 369000, 537098, 737640, 1073674, 1474920, 2146826, 2949480, 4293130, 5898600

Offset

1,1

Links

R. H. Hardin, Table of n, a(n) for n = 1..210

Formula

Empirical: a(n) = 3*a(n-2) - 2*a(n-4) for n>10.

Empirical g.f.: 2*x*(1020 + 614*x - 2832*x^2 - 1511*x^3 + 1632*x^4 + 629*x^5 - 12*x^6 + 3*x^7 + 12*x^8 + 4*x^9) / ((1 - x)*(1 + x)*(1 - 2*x^2)). - Colin Barker, Dec 24 2018

Example

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

Crossrefs

Column 7 of A258966.

Sequence in context: A020413 A031806 A186045 * A250009 A015158 A015286

Adjacent sequences: A258962 A258963 A258964 * A258966 A258967 A258968

Keyword

nonn

Author

R. H. Hardin, Jun 15 2015

Status

approved