A297546 Number of 3Xn 0..1 arrays with every 1 horizontally, diagonally or antidiagonally adjacent to 2 or 3 neighboring 1s.

1, 4, 35, 93, 197, 905, 4617, 17190, 60751, 249752, 1059063, 4222592, 16594402, 66999457, 272610044, 1096920548, 4397739438, 17715067000, 71488573309, 287925302744, 1158665331861, 4666508501343, 18801789510992, 75728618048706

Offset

1,2

Comments

Row 3 of A297544.

Links

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

Formula

Empirical: a(n) = 4*a(n-1) -4*a(n-2) +17*a(n-3) +22*a(n-4) -76*a(n-5) -55*a(n-6) -66*a(n-7) -151*a(n-8) +47*a(n-9) +101*a(n-10) -39*a(n-11) +43*a(n-12) +60*a(n-13) -21*a(n-14) +7*a(n-15) +2*a(n-16) +a(n-17)

Example

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

Crossrefs

Cf. A297544.

Sequence in context: A282284 A003349 A344642 * A257600 A211612 A068968

Adjacent sequences: A297543 A297544 A297545 * A297547 A297548 A297549

Keyword

nonn

Author

R. H. Hardin, Dec 31 2017

Status

approved