A303631 Number of n X 3 0..1 arrays with every element unequal to 2 or 3 horizontally or vertically adjacent elements, with upper left element zero.

0, 1, 0, 1, 0, 3, 2, 9, 12, 33, 56, 129, 244, 523, 1034, 2153, 4336, 8921, 18104, 37065, 75456, 154171, 314266, 641569, 1308492, 2670345, 5447424, 11115417, 22677188, 46269875, 94401330, 192609073, 392973504, 801784337, 1635862800, 3337639217

Offset

1,6

Comments

Column 3 of A303636.

Links

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

Formula

Empirical: a(n) = a(n-1) +2*a(n-2) +a(n-4) -a(n-5).

Example

All solutions for n=4:
..0..1..0
..1..0..1
..1..0..1
..0..1..0

Crossrefs

Cf. A303636.

Sequence in context: A053151 A053088 A077898 * A358603 A076584 A309673

Adjacent sequences: A303628 A303629 A303630 * A303632 A303633 A303634

Keyword

nonn

Author

R. H. Hardin, Apr 27 2018

Status

approved