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

1,1

Links

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

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

Example

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

Crossrefs

Column 7 of A281205.

Sequence in context: A221870 A289181 A056114 * A186259 A292281 A056932

Adjacent sequences: A281201 A281202 A281203 * A281205 A281206 A281207

Keyword

nonn

Author

R. H. Hardin, Jan 17 2017

Status

approved