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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
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
KEYWORD
nonn
AUTHOR
R. H. Hardin, Apr 27 2018
STATUS
approved

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Last modified June 19 23:45 EDT 2024. Contains 373510 sequences. (Running on oeis4.)