A297751 Number of 3Xn 0..1 arrays with every 1 horizontally, diagonally or antidiagonally adjacent to 1, 3 or 4 neighboring 1s.

1, 11, 66, 174, 452, 2223, 9733, 32213, 109959, 444222, 1741686, 6270922, 22908011, 87743411, 332882553, 1231723189, 4581917598, 17276990320, 64938750220, 242324446545, 905905664957, 3399845574813, 12746035541887, 47685495021184

Offset

1,2

Comments

Row 3 of A297749.

Links

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

Formula

Empirical: a(n) = 2*a(n-1) +a(n-2) +14*a(n-3) +49*a(n-4) -41*a(n-5) -129*a(n-6) -172*a(n-7) -96*a(n-8) +68*a(n-9) +88*a(n-10) +150*a(n-11) +121*a(n-12) +a(n-13) +15*a(n-14) -32*a(n-15) -7*a(n-16) -14*a(n-17) -3*a(n-18) +2*a(n-19)

Example

Some solutions for n=7
..1..1..1..0..1..0..0. .1..0..1..0..1..0..1. .0..1..0..0..1..0..1
..1..0..0..0..1..1..1. .0..1..0..0..0..1..1. .0..0..1..0..1..1..1
..0..0..0..0..0..0..0. .0..1..1..1..0..0..0. .0..0..0..0..0..0..0

Crossrefs

Cf. A297749.

Sequence in context: A260151 A139611 A154617 * A063842 A331715 A162628

Adjacent sequences: A297748 A297749 A297750 * A297752 A297753 A297754

Keyword

nonn

Author

R. H. Hardin, Jan 05 2018

Status

approved