A258675 Number of (n+2) X (2+2) 0..1 arrays with no 3 x 3 subblock diagonal sum equal to the antidiagonal sum.

1600, 10000, 67600, 456976, 2944656, 18974736, 125888400, 835210000, 5443488400, 35477982736, 233749042576, 1540071072016, 10079990010000, 65975006250000, 433559848410000, 2849172024948496, 18677605395953296, 122440112521198096

Offset

1,1

Links

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

Formula

Empirical: a(n) = 9*a(n-1) - 36*a(n-2) + 180*a(n-3) - 2880*a(n-5) + 9216*a(n-6) - 36864*a(n-7) + 65536*a(n-8).

Empirical g.f.: 16*x*(100 - 275*x + 2200*x^2 - 4964*x^3 - 33408*x^4 + 85248*x^5 - 442368*x^6 + 1048576*x^7) / ((1 - 4*x)*(1 + 4*x)*(1 - 9*x + 16*x^2)*(1 + 36*x^2 + 256*x^4)). - Colin Barker, Dec 22 2018

Example

Some solutions for n=3:
..1..1..1..1....1..0..1..1....0..1..0..1....1..1..1..1....0..0..0..0
..1..0..0..0....0..1..1..0....1..0..0..0....1..0..1..0....1..0..1..1
..0..0..1..1....0..1..1..0....0..1..1..0....1..0..0..1....1..0..0..1
..0..0..0..1....1..0..0..0....0..1..0..0....1..0..0..1....1..0..0..0
..1..0..1..0....0..0..0..0....1..1..1..1....0..1..1..1....0..1..1..0

Crossrefs

Column 2 of A258681.

Sequence in context: A309562 A043412 A202096 * A236992 A251969 A206250

Adjacent sequences: A258672 A258673 A258674 * A258676 A258677 A258678

Keyword

nonn

Author

R. H. Hardin, Jun 07 2015

Status

approved