A230911 Number of n X 4 0..7 arrays x(i,j) with each element horizontally or antidiagonally next to at least one element with value (x(i,j)+1) mod 8, and upper left element zero.

0, 0, 8, 118, 1506, 20028, 271450, 3678640, 49775880, 673343864, 9109364398, 123240784402, 1667327405972, 22557246670250, 305176478640952, 4128726222060840, 55857454913515424, 755694397322454686

Offset

1,3

Links

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

Formula

Empirical: a(n) = 18*a(n-1) - 91*a(n-2) + 469*a(n-3) - 919*a(n-4) + 2152*a(n-5) - 93*a(n-6) + a(n-7).

Empirical g.f.: 2*x^3*(1 - x)*(4 - 9*x + 46*x^2 - x^3) / (1 - 18*x + 91*x^2 - 469*x^3 + 919*x^4 - 2152*x^5 + 93*x^6 - x^7). - Colin Barker, Sep 22 2018

Example

Some solutions for n=3:
..0..1..0..7....0..1..4..5....0..1..2..1....0..1..2..3....0..1..2..3
..2..3..6..5....2..3..6..7....0..3..0..7....0..1..4..5....0..7..4..3
..4..5..4..3....2..1..0..7....4..5..6..5....0..7..6..5....6..5..4..3

Crossrefs

Column 4 of A230915.

Sequence in context: A341197 A342182 A194494 * A267752 A318009 A368911

Adjacent sequences: A230908 A230909 A230910 * A230912 A230913 A230914

Keyword

nonn

Author

R. H. Hardin, Nov 01 2013

Status

approved