A302070 Number of 3Xn 0..1 arrays with every element equal to 0, 1, 2 or 4 horizontally or antidiagonally adjacent elements, with upper left element zero.

4, 32, 148, 748, 3657, 18108, 89658, 444359, 2202106, 10912859, 54080195, 268002332, 1328125172, 6581720890, 32616691234, 161636836900, 801015249307, 3969549529089, 19671689743540, 97485967746453, 483106130247259

Offset

1,1

Comments

Row 3 of A302069.

Links

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

Formula

Empirical: a(n) = 4*a(n-1) +4*a(n-2) +2*a(n-3) +7*a(n-4) +7*a(n-5) -4*a(n-6) -10*a(n-7) -3*a(n-8) -5*a(n-9) -11*a(n-10) +2*a(n-11) +8*a(n-12) +a(n-13) -a(n-15) for n>18

Example

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

Crossrefs

Cf. A302069.

Sequence in context: A123854 A301843 A332430 * A302267 A113154 A302966

Adjacent sequences: A302067 A302068 A302069 * A302071 A302072 A302073

Keyword

nonn

Author

R. H. Hardin, Mar 31 2018

Status

approved