A241256 Number of 2 X n 0..3 arrays with no element equal to one plus the sum of elements to its left or zero plus the sum of the elements above it or one plus the sum of the elements diagonally to its northwest or zero plus the sum of the elements antidiagonally to its northeast, modulo 4.

2, 5, 4, 10, 12, 22, 41, 59, 120, 171, 306, 494, 784, 1345, 2112, 3547, 5782, 9402, 15643, 25307, 41868, 68465, 112078, 184535, 301346, 495580, 811726, 1330658, 2184497, 3577622, 5872217, 9625155, 15783147, 25889388, 42437724, 69611469, 114132047

Offset

1,1

Links

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

Formula

Empirical: a(n) = 2*a(n-2) + 2*a(n-3) - a(n-4) - a(n-5) - a(n-6) + a(n-7) + 2*a(n-8) + a(n-10) for n>12.

Empirical g.f.: x*(2 + 5*x - 4*x^3 - 4*x^4 + x^5 + 8*x^6 + 8*x^7 + 11*x^8 + x^9 + 3*x^10 - 3*x^11) / ((1 + x)*(1 - x - x^2 - x^3 + 2*x^4 - x^5 + 2*x^6 - 3*x^7 + x^8 - x^9)). - Colin Barker, Oct 29 2018

Example

Some solutions for n=4:
..3..3..2..2....2..2..3..3....2..2..3..3....2..2..3..3....2..2..3..3
..2..1..3..1....3..1..2..1....0..0..0..2....3..1..0..2....0..0..2..1

Crossrefs

Row 2 of A241255.

Sequence in context: A071297 A356875 A114393 * A230435 A180338 A232646

Adjacent sequences: A241253 A241254 A241255 * A241257 A241258 A241259

Keyword

nonn

Author

R. H. Hardin, Apr 18 2014

Status

approved