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A317858
Number of nX3 0..1 arrays with every element unequal to 1, 2 or 4 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.
1
1, 6, 4, 19, 32, 72, 164, 331, 790, 1700, 3879, 8689, 19763, 44787, 101708, 232136, 528496, 1206975, 2755982, 6298876, 14399412, 32932776, 75341117, 172383450, 394513860, 902958422, 2066919648, 4731632878, 10832452949, 24800620478
OFFSET
1,2
COMMENTS
Column 3 of A317863.
LINKS
FORMULA
Empirical: a(n) = 5*a(n-2) +8*a(n-3) -2*a(n-4) -26*a(n-5) -32*a(n-6) +6*a(n-7) +40*a(n-8) +32*a(n-9) -3*a(n-10) -16*a(n-11) +17*a(n-12) +6*a(n-13) -20*a(n-14) -6*a(n-15) +19*a(n-16) +14*a(n-17) -14*a(n-19) -5*a(n-20) +2*a(n-21) -10*a(n-22) +3*a(n-24) +a(n-26) for n>32
EXAMPLE
Some solutions for n=5
..0..1..0. .0..1..1. .0..1..0. .0..0..0. .0..1..1. .0..1..0. .0..1..0
..0..0..1. .0..1..0. .0..0..0. .1..1..0. .1..1..0. .1..1..0. .1..1..0
..1..1..1. .0..0..0. .1..0..1. .1..0..1. .1..1..1. .0..0..0. .1..1..0
..1..0..0. .1..0..1. .0..0..0. .0..1..1. .0..1..1. .0..1..1. .0..0..0
..0..1..0. .0..0..0. .0..1..0. .0..0..0. .1..0..1. .1..0..1. .0..1..0
CROSSREFS
Cf. A317863.
Sequence in context: A213761 A160248 A356044 * A375673 A212891 A107983
KEYWORD
nonn
AUTHOR
R. H. Hardin, Aug 09 2018
STATUS
approved