A281204 Number of n X 7 0..1 arrays with no element equal to more than one of its horizontal and antidiagonal neighbors, with the exception of exactly one element, and with new values introduced in order 0 sequentially upwards.

20, 166, 537, 1358, 3137, 6838, 14375, 29416, 58984, 116466, 227134, 438532, 839659, 1596460, 3017310, 5673426, 10619999, 19801344, 36791933, 68149580, 125882603, 231941798, 426388234, 782226746, 1432314394, 2618121324, 4778002317

Offset: 1

Author

R. H. Hardin, Jan 17 2017

Keywords

• nonn

Examples

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

Links

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

Crossrefs

Column 7 of A281205.

Formula

Empirical: a(n) = 4*a(n-1) - 4*a(n-2) - 2*a(n-4) + 4*a(n-5) - 2*a(n-6) + 4*a(n-7) - a(n-8) - 2*a(n-10) - a(n-12).

Empirical g.f.: x*(20 + 86*x - 47*x^2 - 126*x^3 - 107*x^4 - 26*x^5 + 21*x^6 + 88*x^7 + 92*x^8 + 56*x^9 + 23*x^10 + 10*x^11) / ((1 - 2*x + x^2 - x^3)^2*(1 - x^2 - x^3)^2). - Colin Barker, Feb 18 2019