A296400 Number of nX3 0..1 arrays with each 1 horizontally, vertically or antidiagonally adjacent to 2 or 3 neighboring 1s.

1, 8, 24, 82, 316, 1182, 4560, 17508, 67310, 259398, 999368, 3851828, 14846772, 57226834, 220589358, 850295818, 3277615080, 12634174925, 48700783032, 187726368115, 723626846696, 2789356995974, 10752106442068, 41446037382414

Offset

1,2

Comments

Column 3 of A296405.

Links

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

Formula

Empirical: a(n) = 5*a(n-1) -6*a(n-2) +8*a(n-3) -10*a(n-4) +22*a(n-5) -50*a(n-6) +37*a(n-7) -59*a(n-8) -3*a(n-10) -50*a(n-11) +10*a(n-12) -36*a(n-13) -17*a(n-14) -7*a(n-15) -19*a(n-16) -7*a(n-17) -4*a(n-18) -4*a(n-19) -a(n-20)

Example

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

Crossrefs

Cf. A296405.

Sequence in context: A141317 A146534 A180888 * A297808 A097544 A128688

Adjacent sequences: A296397 A296398 A296399 * A296401 A296402 A296403

Keyword

nonn

Author

R. H. Hardin, Dec 11 2017

Status

approved