A278001 Number of nX3 0..2 arrays with every element plus 1 mod 3 equal to some element at offset (-1,-1) (-1,0) (-1,1) (0,-1) (0,1) (1,-1) or (1,0), with upper left element zero.

0, 52, 866, 16583, 316432, 6031565, 114975158, 2191741025, 41780404363, 796445224559, 15182359059263, 289416039476474, 5517037468209865, 105169369667173021, 2004807177668663124, 38216943130107881653

Offset

1,2

Comments

Column 3 of A278006.

Links

R. H. Hardin, Table of n, a(n) for n = 1..210

Formula

Empirical: a(n) = 18*a(n-1) +21*a(n-2) +15*a(n-3) -530*a(n-4) -562*a(n-5) +986*a(n-6) +5831*a(n-7) -1452*a(n-8) -8962*a(n-9) -19556*a(n-10) +24096*a(n-11) +21600*a(n-12) +12480*a(n-13) -45824*a(n-14) +3456*a(n-15) -768*a(n-16)

Example

Some solutions for n=4
..0..2..1. .0..2..1. .0..1..0. .0..1..2. .0..1..2. .0..0..1. .0..1..0
..1..2..1. .1..2..0. .2..0..2. .2..0..2. .0..1..0. .1..2..1. .0..2..1
..0..1..0. .2..0..1. .2..0..2. .1..2..2. .2..2..0. .1..0..1. .1..0..0
..2..1..2. .1..1..0. .1..1..1. .1..1..1. .1..1..2. .0..0..0. .2..1..2

Crossrefs

Cf. A278006.

Sequence in context: A163691 A007247 A232312 * A083936 A273655 A160288

Adjacent sequences: A277998 A277999 A278000 * A278002 A278003 A278004

Keyword

nonn

Author

R. H. Hardin, Nov 08 2016

Status

approved