A239399 Number of n X 2 0..3 arrays with no element equal to one plus the sum of elements to its left or two plus the sum of elements above it, modulo 4.

4, 23, 129, 698, 3805, 20818, 113774, 621754, 3399032, 18582965, 101593258, 555419633, 3036563927, 16601366841, 90762262155, 496211843813, 2712870511114, 14831702705726, 81087325012785, 443317575022163, 2423689199017701, 13250702601112477, 72443743963082659, 396061718589309511

Offset

1,1

Links

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

Formula

Empirical: a(n) = 9*a(n-1) -28*a(n-2) +74*a(n-3) -181*a(n-4) +236*a(n-5) -261*a(n-6) +234*a(n-7) +200*a(n-8) -279*a(n-9) +104*a(n-10) -268*a(n-11) -36*a(n-12) +156*a(n-13) +104*a(n-14) -32*a(n-15) -16*a(n-16).

Example

Some solutions for n=5:
..3..1....0..0....0..3....0..0....3..3....3..3....3..3....3..1....3..1....0..0
..0..0....3..1....3..3....0..3....3..3....0..0....3..3....0..2....0..2....0..0
..2..2....2..2....3..2....0..2....3..2....2..0....2..2....0..2....0..2....0..0
..2..0....2..2....3..1....0..2....0..3....0..3....3..1....2..0....0..0....3..3
..3..2....3..1....2..0....0..0....2..0....0..2....3..1....0..0....0..2....0..0

Crossrefs

Column 2 of A239405.

Sequence in context: A236421 A227639 A291026 * A193808 A038723 A302761

Adjacent sequences: A239396 A239397 A239398 * A239400 A239401 A239402

Keyword

nonn

Author

R. H. Hardin, Mar 17 2014

Status

approved