A266132 Number of 2Xn integer arrays with each element equal to the number of horizontal, diagonal and antidiagonal neighbors exactly one smaller than itself.

1, 9, 25, 49, 149, 625, 2141, 5433, 17269, 65249, 214877, 600025, 1934485, 6961153, 22488637, 66171721, 214994149, 746222545, 2392193165, 7273608601, 23705004725, 80233190113, 256613628509, 797094034921, 2598493640773, 8647653815601

Offset: 1

Author

R. H. Hardin, Dec 21 2015

Keywords

• nonn

Comments

Row 2 of A266131.

Examples

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

Links

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

Crossrefs

Cf. A266131.

Formula

Empirical: a(n) = a(n-1) +8*a(n-3) +80*a(n-4) -40*a(n-5) -52*a(n-6) -112*a(n-7) -1204*a(n-8) +292*a(n-9) +64*a(n-10) -880*a(n-11) +4016*a(n-12) -2112*a(n-13) -1152*a(n-14) +1024*a(n-15) -4608*a(n-16) +4608*a(n-17)