A297433 Number of 3Xn 0..1 arrays with every 1 horizontally, diagonally or antidiagonally adjacent to 2 neighboring 1s.

1, 3, 14, 26, 43, 109, 301, 649, 1332, 3124, 7545, 16925, 37301, 85611, 198538, 450262, 1014883, 2315761, 5303161, 12062833, 27380904, 62381096, 142295761, 323928537, 736878729, 1678132851, 3823284742, 8705263890, 19816325051, 45124192277

Offset

1,2

Comments

Row 3 of A297431.

Links

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

Formula

Empirical: a(n) = a(n-1) +3*a(n-3) +8*a(n-4) +a(n-5) -a(n-6).

Empirical: G.f.: -x*(-1-2*x-11*x^2-9*x^3+x^5)/(1-x-3*x^3-8*x^4-x^5+x^6) . - R. J. Mathar, Feb 13 2018

Example

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

Crossrefs

Cf. A297431.

Sequence in context: A017425 A302758 A063098 * A032300 A032212 A032137

Adjacent sequences: A297430 A297431 A297432 * A297434 A297435 A297436

Keyword

nonn

Author

R. H. Hardin, Dec 30 2017

Status

approved