A230964 Number of n X 2 0..3 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 4 and at least one element with value (x(i,j)-1) mod 4, and upper left element zero.

0, 6, 22, 200, 1732, 14384, 121696, 1027464, 8672840, 73227432, 618256792, 5219942472, 44072147576, 372102417096, 3141672058936, 26525234659400, 223953378903736, 1890845334033992, 15964465905002424, 134788481690623048

Offset

1,2

Links

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

Formula

Empirical: a(n) = 7*a(n-1) + 10*a(n-2) + 38*a(n-3) - 132*a(n-4) - 232*a(n-5) - 448*a(n-6) + 320*a(n-7) + 256*a(n-8).

Empirical g.f.: 2*x^2*(3 - 10*x - 7*x^2 - 58*x^3 + 108*x^4 + 192*x^5 + 64*x^6) / (1 - 7*x - 10*x^2 - 38*x^3 + 132*x^4 + 232*x^5 + 448*x^6 - 320*x^7 - 256*x^8). - Colin Barker, Sep 24 2018

Example

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

Crossrefs

Column 2 of A230968.

Sequence in context: A028406 A090372 A009366 * A075811 A302926 A121796

Adjacent sequences: A230961 A230962 A230963 * A230965 A230966 A230967

Keyword

nonn

Author

R. H. Hardin, Nov 02 2013

Status

approved