A268882 Number of n X 4 binary arrays with some element plus some horizontally or antidiagonally adjacent neighbor totalling two exactly once.

5, 54, 501, 4133, 31956, 236960, 1706732, 12034000, 83485488, 571836176, 3876692480, 26059576704, 173934499008, 1153927868416, 7615733792000, 50035609197824, 327432063642624, 2135189929320448, 13880060602788864

Offset

1,1

Links

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

Formula

Empirical: a(n) = 16*a(n-1) - 88*a(n-2) + 200*a(n-3) - 208*a(n-4) + 96*a(n-5) - 16*a(n-6) for n>7.

Empirical g.f.: x*(5 - 26*x + 77*x^2 - 131*x^3 + 156*x^4 - 80*x^5 + 4*x^6) / (1 - 8*x + 12*x^2 - 4*x^3)^2. - Colin Barker, Jan 15 2019

Example

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

Crossrefs

Column 4 of A268886.

Sequence in context: A208429 A275353 A221544 * A229298 A087125 A110430

Adjacent sequences: A268879 A268880 A268881 * A268883 A268884 A268885

Keyword

nonn

Author

R. H. Hardin, Feb 15 2016

Status

approved