A303103 Number of 3Xn 0..1 arrays with every element equal to 1, 2, 3, 4 or 6 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.

0, 11, 77, 431, 2913, 19393, 128921, 857789, 5706297, 37961366, 252538085, 1680012401, 11176296913, 74350419884, 494616846377, 3290443118074, 21889703025083, 145621450295042, 968748034460686, 6444605189965405

Offset

1,2

Comments

Row 3 of A303102.

Links

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

Formula

Empirical: a(n) = 5*a(n-1) +11*a(n-2) +a(n-4) -8*a(n-5) -a(n-6) -20*a(n-7) -2*a(n-8) -13*a(n-9) +3*a(n-10) -6*a(n-11) -5*a(n-12) +a(n-13) -2*a(n-14) for n>15

Example

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

Crossrefs

Cf. A303102.

Sequence in context: A059625 A355053 A023010 * A258459 A320547 A022639

Adjacent sequences: A303100 A303101 A303102 * A303104 A303105 A303106

Keyword

nonn

Author

R. H. Hardin, Apr 18 2018

Status

approved