A232377 Number of 2Xn 0..3 arrays with every 0 next to a 1, every 1 next to a 2 and every 2 next to a 3 horizontally, diagonally or antidiagonally, and no adjacent values equal.

1, 14, 74, 296, 1130, 4682, 19448, 79592, 326810, 1343042, 5516132, 22658744, 93073958, 382310690, 1570402928, 6450645104, 26496901994, 108839752922, 447074397188, 1836420218672, 7543351642070, 30985365821066, 127276699845344, 522806747988728, 2147501432084138

Offset

1,2

Comments

Row 2 of A232376.

Links

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

Formula

Empirical: a(n) = 3*a(n-1) +a(n-2) +13*a(n-3) +26*a(n-5) -4*a(n-6) +24*a(n-7) +16*a(n-8) for n>9.

Empirical g.f.: x + 2*x^2*(-7 -16*x -30*x^2 +7*x^3 -17*x^4 -30*x^5 -4*x^6 +8*x^7) / ( (2*x^2+1)*(8*x^6 +12*x^5 -6*x^4 +7*x^3 +3*x^2 +3*x-1) ). - R. J. Mathar, Nov 27 2013

Example

Some solutions for n=7
..3..0..1..2..1..0..3....0..3..2..3..0..3..0....2..1..2..3..0..3..2
..3..2..3..0..1..0..3....2..1..0..3..2..1..0....2..3..2..3..0..1..2

Crossrefs

Sequence in context: A205590 A369244 A213284 * A146563 A205583 A167633

Adjacent sequences: A232374 A232375 A232376 * A232378 A232379 A232380

Keyword

nonn

Author

R. H. Hardin, Nov 23 2013

Status

approved