A302417 Number of 4Xn 0..1 arrays with every element equal to 0, 1, 2 or 5 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.

8, 81, 120, 259, 698, 1650, 3655, 8544, 20246, 47274, 110507, 259419, 607197, 1420291, 3328378, 7799749, 18264688, 42776207, 100206573, 234721284, 549779626, 1287794595, 3016512620, 7065696896, 16550376724, 38767164617, 90806809133

Offset

1,1

Comments

Row 4 of A302415.

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) +6*a(n-3) -6*a(n-4) +3*a(n-5) -6*a(n-6) +a(n-7) -14*a(n-8) +9*a(n-9) +4*a(n-10) +2*a(n-11) -4*a(n-12) +2*a(n-13) +8*a(n-15) -4*a(n-16) for n>21

Example

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

Crossrefs

Cf. A302415.

Sequence in context: A210134 A274855 A301939 * A227227 A303184 A302325

Adjacent sequences: A302414 A302415 A302416 * A302418 A302419 A302420

Keyword

nonn

Author

R. H. Hardin, Apr 07 2018

Status

approved