A280437 Number of n X 5 0..1 arrays with no element equal to more than one of its horizontal and vertical neighbors, with the exception of exactly one element, and with new values introduced in order 0 sequentially upwards.

5, 38, 77, 138, 225, 360, 574, 920, 1487, 2422, 3971, 6542, 10814, 17914, 29713, 49314, 81861, 135876, 225470, 373996, 620083, 1027598, 1702087, 2817898, 4662910, 7712270, 12749909, 21068730, 34800297, 57457632, 94828606, 156445952

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-3) + 4*a(n-4) - a(n-6) for n>7.

Empirical g.f.: x*(5 + 18*x - 55*x^2 - 8*x^3 + 37*x^4 + 14*x^5 + 7*x^6) / ((1 - x)^2*(1 - x - x^2)^2). - Colin Barker, Feb 13 2019

Example

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

Crossrefs

Column 5 of A280440.

Sequence in context: A061674 A247709 A097276 * A222646 A145156 A318102

Adjacent sequences: A280434 A280435 A280436 * A280438 A280439 A280440

Keyword

nonn

Author

R. H. Hardin, Jan 03 2017

Status

approved