login
A239643
Number of nX2 0..3 arrays with no element equal to zero plus the sum of elements to its left or two plus the sum of elements above it, modulo 4
1
4, 20, 112, 560, 2874, 14788, 75540, 387306, 1983686, 10160422, 52047250, 266599168, 1365605466, 6995075202, 35830971136, 183537592492, 940137864960, 4815683846868, 24667460086554, 126354551389040, 647228071957412
OFFSET
1,1
COMMENTS
Column 2 of A239649
LINKS
FORMULA
Empirical: a(n) = a(n-1) +16*a(n-2) +31*a(n-3) -8*a(n-4) -78*a(n-5) -45*a(n-6) +56*a(n-7) -32*a(n-8) +32*a(n-9) +16*a(n-10)
EXAMPLE
Some solutions for n=5
..1..0....1..3....3..1....3..1....1..0....1..0....1..0....1..0....3..1....1..0
..1..3....2..0....3..2....3..2....2..0....2..1....2..1....2..0....3..2....1..0
..2..0....3..2....3..2....2..0....3..0....3..0....3..0....3..1....1..2....1..3
..1..0....2..0....1..0....1..3....3..0....2..1....2..1....3..0....3..0....3..2
..2..0....3..0....3..0....1..2....2..0....3..1....1..2....1..2....2..0....2..0
CROSSREFS
Sequence in context: A025183 A014523 A153299 * A081335 A136783 A227726
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 23 2014
STATUS
approved