A256022 Number of (n+2) X (1+2) 0..1 arrays with no 3 x 3 subblock diagonal sum 0 or 1 and no antidiagonal sum 0 or 1 and no row sum 1 and no column sum 1.

33, 68, 154, 352, 798, 1804, 4086, 9304, 21194, 48176, 109506, 249120, 566754, 1289056, 2931842, 6668688, 15168650, 34502104, 78476674, 178499728, 406009530, 923494792, 2100545026, 4777818256, 10867446266, 24718685528, 56224184050

Offset

1,1

Links

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

Formula

Empirical: a(n) = 2*a(n-1) -a(n-2) +4*a(n-3) -2*a(n-6) -4*a(n-7) +2*a(n-9) for n>10.

Empirical g.f.: x*(33 + 2*x + 51*x^2 - 20*x^3 - 24*x^4 - 56*x^5 - 66*x^6 + 12*x^7 + 36*x^8 + 2*x^9) / ((1 - x)*(1 - x - 4*x^3 - 4*x^4 - 4*x^5 - 2*x^6 + 2*x^7 + 2*x^8)). - Colin Barker, Dec 20 2018

Example

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

Crossrefs

Column 1 of A256029.

Sequence in context: A032661 A256029 A055078 * A044135 A044516 A015722

Adjacent sequences: A256019 A256020 A256021 * A256023 A256024 A256025

Keyword

nonn

Author

R. H. Hardin, Mar 13 2015

Status

approved