A295526 Number of nX3 0..1 arrays with each 1 horizontally or vertically adjacent to 1, 2 or 4 1s.

4, 29, 147, 774, 4080, 21489, 113466, 598374, 3155426, 16642084, 87770692, 462903372, 2441353234, 12875695490, 67906455891, 358138834199, 1888825058236, 9961667898631, 52537860596653, 277084804179135, 1461345928848848

Offset

1,1

Comments

Column 3 of A295531.

Links

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

Formula

Empirical: a(n) = 4*a(n-1) +3*a(n-2) +15*a(n-3) +17*a(n-4) +40*a(n-5) -6*a(n-6) -12*a(n-7) +45*a(n-8) -21*a(n-9) -66*a(n-10) +7*a(n-11) +6*a(n-12) -6*a(n-13) +6*a(n-14) +a(n-15) -3*a(n-16) +a(n-18)

Example

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

Crossrefs

Cf. A295531.

Sequence in context: A273074 A247748 A295035 * A272373 A273247 A302260

Adjacent sequences: A295523 A295524 A295525 * A295527 A295528 A295529

Keyword

nonn

Author

R. H. Hardin, Nov 23 2017

Status

approved