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A210407
Number of (n+1) X 3 0..3 arrays with every 2 X 2 subblock having three or four distinct values, and new values 0..3 introduced in row major order.
1
78, 2520, 80496, 2574592, 82334080, 2633043200, 84204544256, 2692856218368, 86117376515328, 2754028420465408, 88073659990146304, 2816590245285823232, 90074383313881529600, 2880573254472884060928, 92120556023893690612992
OFFSET
1,1
COMMENTS
Column 2 of A210413.
LINKS
FORMULA
Empirical: a(n) = 31*a(n-1) + 40*a(n-2) - 280*a(n-3) + 96*a(n-4).
Empirical g.f.: 2*x*(39 + 51*x - 372*x^2 + 128*x^3) / (1 - 31*x - 40*x^2 + 280*x^3 - 96*x^4). - Colin Barker, Jul 15 2018
EXAMPLE
Some solutions for n=4:
..0..0..1....0..0..0....0..0..0....0..1..0....0..0..0....0..0..0....0..0..0
..1..2..0....1..2..1....1..2..3....2..1..2....1..2..3....1..2..1....1..2..1
..0..1..2....3..2..3....0..1..2....1..0..3....3..2..1....2..3..0....1..0..0
..0..3..3....1..3..0....1..3..0....2..3..1....1..0..3....1..3..1....1..2..3
..0..1..0....2..1..1....0..1..3....0..0..2....3..0..1....3..0..1....3..0..3
CROSSREFS
Cf. A210413.
Sequence in context: A262063 A140934 A133239 * A146479 A017794 A035734
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 21 2012
STATUS
approved