A301965 Number of 3Xn 0..1 arrays with every element equal to 0, 1 or 4 horizontally or antidiagonally adjacent elements, with upper left element zero.

4, 13, 16, 25, 41, 74, 132, 239, 437, 800, 1468, 2697, 4957, 9114, 16760, 30823, 56689, 104264, 191768, 352713, 648737, 1193210, 2194652, 4036591, 7424445, 13655680, 25116708, 46196825, 84969205, 156282730, 287448752, 528700679, 972432153

Offset

1,1

Comments

Row 3 of A301964.

Links

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

Formula

Empirical: a(n) = 2*a(n-1) -a(n-4) for n>6

Example

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

Crossrefs

Cf. A301964.

Sequence in context: A297363 A031208 A228137 * A191135 A268524 A032824

Adjacent sequences: A301962 A301963 A301964 * A301966 A301967 A301968

Keyword

nonn

Author

R. H. Hardin, Mar 29 2018

Status

approved