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A300534
Number of nX3 0..1 arrays with every element equal to 0, 2, 3 or 4 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.
1
1, 5, 12, 36, 122, 429, 1585, 5755, 21084, 77823, 286982, 1060139, 3917406, 14477542, 53517820, 197837108, 731366681, 2703796615, 9995728589, 36953720967, 136616452365, 505066168745, 1867213688572, 6903032086068, 25520304669843
OFFSET
1,2
COMMENTS
Column 3 of A300539.
LINKS
FORMULA
Empirical: a(n) = 2*a(n-1) +7*a(n-2) +6*a(n-3) -21*a(n-4) -36*a(n-5) -26*a(n-6) +4*a(n-7) +62*a(n-8) +82*a(n-9) +18*a(n-10) -52*a(n-11) -42*a(n-12) +72*a(n-13) +38*a(n-14) +12*a(n-15) -25*a(n-16) -16*a(n-17) -4*a(n-18) -6*a(n-19) +8*a(n-20) -4*a(n-21) +2*a(n-22) for n>24
EXAMPLE
Some solutions for n=5
..0..0..0. .0..1..1. .0..0..1. .0..0..1. .0..0..0. .0..0..1. .0..0..0
..0..1..0. .1..0..1. .0..1..1. .0..1..1. .0..1..0. .0..1..1. .0..1..0
..0..0..0. .1..1..0. .0..0..0. .1..1..1. .0..0..0. .1..0..1. .0..0..0
..0..1..1. .0..1..1. .0..0..1. .0..0..0. .0..1..0. .1..1..1. .1..1..1
..1..1..1. .1..1..1. .0..1..1. .0..0..1. .0..0..0. .0..1..1. .1..1..0
CROSSREFS
Cf. A300539.
Sequence in context: A301873 A368094 A077918 * A359189 A297909 A220705
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 08 2018
STATUS
approved