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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. 1
0, 0, 8, 118, 1506, 20028, 271450, 3678640, 49775880, 673343864, 9109364398, 123240784402, 1667327405972, 22557246670250, 305176478640952, 4128726222060840, 55857454913515424, 755694397322454686 (list; graph; refs; listen; history; text; internal format)
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 A228752

Adjacent sequences:  A230908 A230909 A230910 * A230912 A230913 A230914

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 01 2013

STATUS

approved

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Last modified October 22 07:06 EDT 2021. Contains 348160 sequences. (Running on oeis4.)