A239249 Number of n X 1 0..4 arrays with no element equal to one plus the sum of elements to its left or one plus the sum of elements above it, modulo 5.

4, 13, 41, 131, 419, 1339, 4279, 13675, 43703, 139667, 446351, 1426459, 4558711, 14568835, 46559423, 148795691, 475524743, 1519693075, 4856670607, 15521061307, 49602570071, 158521051427, 506605276895, 1619020970827, 5174105015335

Offset

1,1

Links

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

Formula

Empirical: a(n) = 3*a(n-1) + 2*a(n-3).

Empirical g.f.: x*(4 + x + 2*x^2) / (1 - 3*x - 2*x^3). - Colin Barker, Oct 25 2018

Example

Some solutions for n=5:
..4....3....2....3....2....0....4....2....0....3....3....0....3....0....4....4
..2....2....2....2....2....2....3....4....3....0....2....0....2....4....4....3
..4....4....2....0....3....4....0....4....0....2....4....2....0....2....2....4
..0....2....3....4....2....3....2....0....2....0....3....0....0....3....0....0
..3....4....4....4....4....4....2....2....3....4....2....4....2....3....3....4

Crossrefs

Column 1 of A239256.

Sequence in context: A190214 A052529 A049222 * A141364 A001453 A005002

Adjacent sequences: A239246 A239247 A239248 * A239250 A239251 A239252

Keyword

nonn

Author

R. H. Hardin, Mar 13 2014

Status

approved