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

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

R. H. Hardin, Table of n, a(n) for n = 1..210

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

Adjacent sequences: A239640 A239641 A239642 * A239644 A239645 A239646

Keyword

nonn

Author

R. H. Hardin, Mar 23 2014

Status

approved