A232516 Number of (1+1) X (n+1) 0..2 arrays with every element next to itself plus and minus one within the range 0..2 horizontally, diagonally or antidiagonally, with no adjacent elements equal.

4, 16, 16, 54, 74, 218, 340, 868, 1494, 3528, 6466, 14494, 27650, 59992, 117432, 249546, 496576, 1041354, 2094122, 4354594, 8815964, 18233764, 37073438, 76414688, 155795194, 320416958, 654414674, 1344022320, 2748080744, 5638905938

Offset

1,1

Comments

Row 1 of A232515.

Links

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

Formula

Empirical: a(n) = 3*a(n-2) +a(n-3) +2*a(n-4) +2*a(n-5).

Empirical: G.f.: -2*x*(2+8*x+2*x^2+x^3+x^4) / ( -1+3*x^2+x^3+2*x^4+2*x^5 ). - R. J. Mathar, Nov 23 2014

Example

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

Crossrefs

Cf. A232515.

Sequence in context: A223876 A223801 A336938 * A220109 A207283 A207479

Adjacent sequences: A232513 A232514 A232515 * A232517 A232518 A232519

Keyword

nonn

Author

R. H. Hardin, Nov 25 2013

Status

approved