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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

%I

%S 0,0,8,118,1506,20028,271450,3678640,49775880,673343864,9109364398,

%T 123240784402,1667327405972,22557246670250,305176478640952,

%U 4128726222060840,55857454913515424,755694397322454686

%N 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.

%H R. H. Hardin, <a href="/A230911/b230911.txt">Table of n, a(n) for n = 1..210</a>

%F 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).

%F 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

%e Some solutions for n=3:

%e ..0..1..0..7....0..1..4..5....0..1..2..1....0..1..2..3....0..1..2..3

%e ..2..3..6..5....2..3..6..7....0..3..0..7....0..1..4..5....0..7..4..3

%e ..4..5..4..3....2..1..0..7....4..5..6..5....0..7..6..5....6..5..4..3

%Y Column 4 of A230915.

%K nonn

%O 1,3

%A _R. H. Hardin_, Nov 01 2013

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Last modified December 6 13:45 EST 2021. Contains 349563 sequences. (Running on oeis4.)