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A277940
Number of nX3 0..2 arrays with every element plus 1 mod 3 equal to some element at offset (-1,0) (-1,1) (0,-1) (0,1) or (1,0), with upper left element zero.
1
0, 14, 172, 2353, 31011, 410047, 5417792, 71585918, 945856876, 12497509310, 165128212197, 2181820850641, 28828157762271, 380903262040913, 5032832696491638, 66498262088947407, 878634186243031144
OFFSET
1,2
COMMENTS
Column 3 of A277945.
LINKS
FORMULA
Empirical: a(n) = 17*a(n-1) -46*a(n-2) -74*a(n-3) +248*a(n-4) +365*a(n-5) -302*a(n-6) -2897*a(n-7) +586*a(n-8) +9050*a(n-9) +1379*a(n-10) -16481*a(n-11) -15496*a(n-12) +28568*a(n-13) +32667*a(n-14) -39070*a(n-15) -26031*a(n-16) +26346*a(n-17) +8108*a(n-18) -5448*a(n-19) -1536*a(n-20) for n>21
EXAMPLE
Some solutions for n=4
..0..2..1. .0..1..2. .0..1..0. .0..1..0. .0..1..2. .0..1..0. .0..2..0
..1..2..0. .2..1..0. .0..2..1. .2..2..2. .0..2..0. .2..2..2. .1..2..1
..1..1..0. .0..2..1. .1..0..0. .0..1..0. .2..0..1. .0..1..0. .1..0..2
..0..2..1. .1..1..0. .0..1..2. .0..1..2. .2..0..2. .2..0..2. .0..2..1
CROSSREFS
Cf. A277945.
Sequence in context: A048443 A191690 A016136 * A061484 A097583 A269680
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 05 2016
STATUS
approved