A283630 Number of nX4 0..1 arrays with no 1 equal to more than one of its horizontal, diagonal and antidiagonal neighbors, with the exception of exactly two elements.

1, 36, 639, 7742, 85469, 856710, 8209582, 75625580, 677582140, 5935472812, 51063145445, 432757594342, 3621630322984, 29983493956274, 245931204265827, 2000828493677966, 16161824873357957, 129718958313978310

Offset

1,2

Comments

Column 4 of A283634.

Links

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

Formula

Empirical: a(n) = 18*a(n-1) -78*a(n-2) -186*a(n-3) +1365*a(n-4) +234*a(n-5) -4523*a(n-6) +15594*a(n-7) +6057*a(n-8) -60614*a(n-9) +66588*a(n-10) +51762*a(n-11) -313536*a(n-12) +181776*a(n-13) +367095*a(n-14) -650452*a(n-15) +214245*a(n-16) +853410*a(n-17) -640177*a(n-18) -457782*a(n-19) +317076*a(n-20) +100568*a(n-21) -60480*a(n-22) -7680*a(n-23) +4096*a(n-24)

Example

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

Crossrefs

Cf. A283634.

Sequence in context: A010952 A323980 A287990 * A035713 A035478 A250624

Adjacent sequences: A283627 A283628 A283629 * A283631 A283632 A283633

Keyword

nonn

Author

R. H. Hardin, Mar 12 2017

Status

approved