A296323 Number of nX4 0..1 arrays with each 1 horizontally, vertically or antidiagonally adjacent to 2 neighboring 1s.

1, 8, 23, 61, 185, 562, 1677, 4998, 14968, 44818, 134061, 401123, 1200360, 3591843, 10747770, 32160619, 96234620, 287963368, 861674203, 2578393448, 7715343389, 23086669802, 69082386936, 206715662599, 618556579000, 1850910743566

Offset

1,2

Comments

Column 4 of A296327.

Links

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

Formula

Empirical: a(n) = 4*a(n-1) -6*a(n-2) +13*a(n-3) -17*a(n-4) +22*a(n-5) -30*a(n-6) +33*a(n-7) -42*a(n-8) +37*a(n-9) -34*a(n-10) +21*a(n-11) -12*a(n-12) +4*a(n-13) -a(n-14)

Example

Some solutions for n=5
..0..1..1..0. .1..1..0..0. .0..0..0..0. .0..1..1..0. .1..1..0..0
..1..0..1..1. .1..0..0..0. .0..0..1..1. .0..1..0..0. .1..0..0..0
..1..0..0..1. .0..0..0..0. .0..1..0..1. .0..0..1..1. .0..1..0..0
..1..1..0..1. .0..0..0..1. .1..0..1..0. .0..0..1..0. .1..1..0..1
..0..1..1..0. .0..0..1..1. .1..1..0..0. .0..0..0..0. .0..0..1..1

Crossrefs

Cf. A296327.

Sequence in context: A002765 A048770 A055273 * A241353 A362163 A059209

Adjacent sequences: A296320 A296321 A296322 * A296324 A296325 A296326

Keyword

nonn

Author

R. H. Hardin, Dec 10 2017

Status

approved