A303631 - OEIS

The OEIS is supported by the many generous donors to the OEIS Foundation.

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.

1

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

(list; graph; refs; listen; history; text; internal format)

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

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