A283380 Number of nX2 0..1 arrays with no 1 equal to more than two of its horizontal, vertical and antidiagonal neighbors, with the exception of exactly two elements.

0, 1, 3, 19, 91, 399, 1734, 7257, 29754, 120018, 477678, 1880898, 7339875, 28425538, 109368210, 418413378, 1592767290, 6036395895, 22786979315, 85714057229, 321381104832, 1201482684424, 4479736531496, 16661729383449, 61830609817953

Offset

1,3

Comments

Column 2 of A283386.

Links

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

Formula

Empirical: a(n) = 9*a(n-1) -24*a(n-2) +18*a(n-3) -36*a(n-4) +111*a(n-5) -38*a(n-6) +150*a(n-7) -162*a(n-8) +135*a(n-9) -222*a(n-10) +177*a(n-11) -212*a(n-12) +186*a(n-13) -168*a(n-14) +160*a(n-15) -114*a(n-16) +99*a(n-17) -68*a(n-18) +48*a(n-19) -30*a(n-20) +16*a(n-21) -9*a(n-22) +3*a(n-23) -a(n-24)

Example

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

Crossrefs

Cf. A283386.

Sequence in context: A183384 A050863 A376836 * A049153 A074361 A126187

Adjacent sequences: A283377 A283378 A283379 * A283381 A283382 A283383

Keyword

nonn

Author

R. H. Hardin, Mar 06 2017

Status

approved