A281209 Number of 5 X n 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.
0, 130, 448, 676, 1141, 1906, 3137, 5160, 8510, 14084, 23379, 38894, 64795, 108022, 180126, 300318, 500525, 833770, 1388053, 2309332, 3839550, 6379528, 10592935, 17578086, 29151695, 48317346, 80038622, 132514530, 219282785, 362687074
Offset: 1
Keywords
Examples
Some solutions for n=4: ..0..1..0..1. .0..0..0..1. .0..1..0..0. .0..0..0..1. .0..1..1..0 ..0..1..0..1. .1..1..0..1. .0..1..1..0. .0..1..0..1. .0..0..1..0 ..1..0..1..0. .0..1..0..1. .0..0..1..0. .1..0..1..0. .1..0..1..0 ..1..0..0..1. .0..1..0..1. .1..1..1..0. .1..0..1..0. .1..1..0..1 ..1..1..0..1. .0..1..0..0. .0..0..1..1. .1..0..1..0. .0..1..0..1
Links
- R. H. Hardin, Table of n, a(n) for n = 1..210
Crossrefs
Row 5 of A281205.
Formula
Empirical: a(n) = 4*a(n-1) - 4*a(n-2) - 2*a(n-3) + 4*a(n-4) - a(n-6) for n>11.
Empirical g.f.: x^2*(130 - 72*x - 596*x^2 + 489*x^3 + 422*x^4 - 363*x^5 - 56*x^6 + 114*x^7 + 10*x^8 - 4*x^9) / ((1 - x)^2*(1 - x - x^2)^2). - Colin Barker, Feb 18 2019