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A231242
Number of n X 4 0..3 arrays x(i,j) with each element horizontally, diagonally or antidiagonally next to at least one element with value (x(i,j)+1) mod 4, no adjacent elements equal, and upper left element zero.
1
0, 44, 464, 5992, 76136, 968824, 12322784, 156753000, 1993963288, 25364073040, 322641895760, 4104143547136, 52206469041840, 664088714466040, 8447493744195456, 107455749517836112, 1366883297468138664
OFFSET
1,2
LINKS
FORMULA
Empirical: a(n) = 10*a(n-1) + 30*a(n-2) + 53*a(n-3) + 71*a(n-4) - a(n-5) + 6*a(n-6) - 8*a(n-7).
Empirical g.f.: 4*x^2*(11 + 6*x + 8*x^2 - 9*x^3 - 3*x^4 - 3*x^5) / (1 - 10*x - 30*x^2 - 53*x^3 - 71*x^4 + x^5 - 6*x^6 + 8*x^7). - Colin Barker, Sep 27 2018
EXAMPLE
Some solutions for n=4:
..0..1..2..1....0..1..0..3....0..3..0..3....0..1..0..3....0..1..0..3
..2..3..0..3....0..3..2..1....0..1..2..1....0..1..2..1....0..1..2..3
..0..3..0..3....2..1..2..1....2..1..2..3....0..1..2..3....2..3..2..1
..2..1..2..3....2..3..0..3....0..3..0..1....2..3..0..1....0..1..0..1
CROSSREFS
Column 4 of A231246.
Sequence in context: A002613 A094201 A210426 * A221730 A306036 A160150
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 06 2013
STATUS
approved