A230921 Number of nX3 0..2 arrays x(i,j) with each element horizontally, vertically, diagonally or antidiagonally next to at least one element with value (x(i,j)+1) mod 3 and at least one element with value (x(i,j)-1) mod 3, and upper left element zero

0, 54, 408, 8748, 154632, 2772906, 49910578, 896666568, 16116885624, 289664758734, 5206108233414, 93568858583172, 1681702346971604, 30225049467827850, 543231436578960226, 9763437937567004392

Offset

1,2

Comments

Column 3 of A230926

Links

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

Formula

Empirical: a(n) = 14*a(n-1) +64*a(n-2) +169*a(n-3) -514*a(n-4) -1955*a(n-5) -7716*a(n-6) +6758*a(n-7) -16190*a(n-8) -417*a(n-9) -10686*a(n-10) +4005*a(n-11) +1271*a(n-12) +2640*a(n-13) +380*a(n-14) -174*a(n-15) +8*a(n-16) -24*a(n-17)

Example

Some solutions for n=3
..0..0..0....0..0..1....0..0..0....0..1..0....0..2..0....0..1..0....0..1..1
..1..2..1....2..1..2....2..1..2....0..2..1....1..1..0....0..2..2....2..0..2
..0..2..0....0..0..0....1..0..0....1..2..0....0..2..1....1..0..1....1..1..2

Crossrefs

Sequence in context: A090832 A232511 A262853 * A239687 A192216 A238908

Adjacent sequences: A230918 A230919 A230920 * A230922 A230923 A230924

Keyword

nonn

Author

R. H. Hardin, Nov 01 2013

Status

approved