A239031 Number of 4 X n 0..2 arrays with no element equal to the sum of elements to its left or one plus the sum of the elements above it, modulo 3.

4, 11, 28, 59, 110, 189, 306, 473, 704, 1015, 1424, 1951, 2618, 3449, 4470, 5709, 7196, 8963, 11044, 13475, 16294, 19541, 23258, 27489, 32280, 37679, 43736, 50503, 58034, 66385, 75614, 85781, 96948, 109179, 122540, 137099, 152926, 170093, 188674

Offset

1,1

Links

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

Formula

Empirical: a(n) = (1/12)*n^4 - (1/6)*n^3 + (47/12)*n^2 - (29/6)*n + 5.

Conjectures from Colin Barker, Oct 25 2018: (Start)

G.f.: x*(4 - 9*x + 13*x^2 - 11*x^3 + 5*x^4) / (1 - x)^5.

a(n) = 5*a(n-1) - 10*a(n-2) + 10*a(n-3) - 5*a(n-4) + a(n-5) for n>5.

(End)

Example

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

Crossrefs

Row 4 of A239030.

Sequence in context: A269076 A282641 A031127 * A289217 A329141 A090539

Adjacent sequences: A239028 A239029 A239030 * A239032 A239033 A239034

Keyword

nonn

Author

R. H. Hardin, Mar 09 2014

Status

approved