A239852 Number of n X 2 0..3 arrays with no element equal to zero plus the sum of elements to its left or zero plus the sum of elements above it or one plus the sum of the elements diagonally to its northwest or one plus the sum of the elements antidiagonally to its northeast, modulo 4.

2, 3, 5, 4, 5, 5, 6, 10, 11, 15, 16, 21, 26, 32, 41, 48, 62, 74, 94, 115, 142, 177, 216, 271, 331, 413, 508, 629, 779, 960, 1192, 1468, 1821, 2247, 2781, 3439, 4249, 5260, 6496, 8041, 9935, 12290, 15195, 18786, 23236, 28721, 35526, 43916, 54312, 67152, 83033

Offset

1,1

Links

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

Formula

Empirical: a(n) = a(n-2) + a(n-5) for n>9.

Empirical g.f.: x*(2 + 3*x + 3*x^2 + x^3 - x^5 - 2*x^6 + x^8) / (1 - x^2 - x^5). - Colin Barker, Oct 26 2018

Example

All solutions for n=4:
..3..2....3..2....3..2....2..3
..2..3....2..3....2..3....3..0
..2..0....3..0....3..0....3..2
..2..0....2..3....3..2....2..3

Crossrefs

Column 2 of A239858.

Sequence in context: A131296 A371216 A267808 * A263279 A262507 A151679

Adjacent sequences: A239849 A239850 A239851 * A239853 A239854 A239855

Keyword

nonn

Author

R. H. Hardin, Mar 28 2014

Status

approved