A281052 Number of nX4 0..1 arrays with no element equal to more than one of its horizontal and antidiagonal neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards.

1, 34, 239, 1022, 3416, 10112, 27635, 71419, 177320, 426696, 1002035, 2306828, 5224307, 11669686, 25762564, 56301813, 121961820, 262154625, 559637795, 1187392495, 2505484374, 5260557953, 10995496220, 22888340830, 47465895442

Offset

1,2

Comments

Column 4 of A281056.

Links

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

Formula

Empirical: a(n) = 3*a(n-1) +3*a(n-2) -11*a(n-3) -9*a(n-4) +18*a(n-5) +17*a(n-6) -12*a(n-7) -15*a(n-8) +3*a(n-9) +6*a(n-10) -a(n-12) for n>14

Example

Some solutions for n=4
..0..1..0..0. .0..0..0..1. .0..1..1..0. .0..0..0..1. .0..0..1..0
..0..1..1..1. .0..1..0..1. .0..0..0..1. .1..1..0..1. .1..1..0..1
..0..1..0..0. .0..0..0..1. .0..1..0..0. .0..1..0..0. .0..1..0..0
..0..1..0..1. .0..1..0..0. .0..1..1..0. .1..0..1..0. .0..1..0..1

Crossrefs

Cf. A281056.

Sequence in context: A355884 A055716 A233300 * A020872 A302474 A183319

Adjacent sequences: A281049 A281050 A281051 * A281053 A281054 A281055

Keyword

nonn

Author

R. H. Hardin, Jan 13 2017

Status

approved