A230683 Number of n X 4 0..6 arrays x(i,j) with each element horizontally or antidiagonally next to at least one element with value (x(i,j)+1) mod 7, and upper left element zero.

0, 0, 0, 2, 32, 432, 5182, 58298, 631576, 6674138, 69325782, 711282602, 7231989990, 73034927200, 733786949368, 7343388325940, 73265369490452, 729240533644054, 7244986066987314, 71874101544950192, 712213220743687894

Offset

1,4

Links

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

Formula

Empirical: a(n) = 17*a(n-1) - 64*a(n-2) - 66*a(n-3) + 20*a(n-4) + 14*a(n-5) + 671*a(n-6) + 1404*a(n-7) - 76*a(n-8) +a(n-9).

Empirical g.f.: 2*x^4*(1 - x + 8*x^2 + 9*x^3 - 38*x^4 + x^5) / (1 - 17*x + 64*x^2 + 66*x^3 - 20*x^4 - 14*x^5 - 671*x^6 - 1404*x^7 + 76*x^8 - x^9). - Colin Barker, Sep 22 2018

Example

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

Crossrefs

Column 4 of A230686.

Sequence in context: A282881 A230567 A340345 * A294328 A109772 A230131

Adjacent sequences: A230680 A230681 A230682 * A230684 A230685 A230686

Keyword

nonn

Author

R. H. Hardin, Oct 27 2013

Status

approved