A239032 Number of 5 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, 16, 54, 149, 354, 757, 1495, 2773, 4888, 8258, 13456, 21249, 32642, 48927, 71737, 103105, 145528, 202036, 276266, 372541, 495954, 652457, 848955, 1093405, 1394920, 1763878, 2212036, 2752649, 3400594, 4172499, 5086877, 6164265, 7427368, 8901208

Offset

1,1

Links

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

Formula

Empirical: a(n) = (1/144)*n^6 - (17/240)*n^5 + (169/144)*n^4 - (81/16)*n^3 + (1463/72)*n^2 - (1001/30)*n + 25 for n>1.

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

G.f.: x*(4 - 12*x + 26*x^2 - 33*x^3 + 25*x^4 - 6*x^5 - 3*x^6 + 4*x^7) / (1 - x)^7.

a(n) = 7*a(n-1) - 21*a(n-2) + 35*a(n-3) - 35*a(n-4) + 21*a(n-5) - 7*a(n-6) + a(n-7) for n>8.

(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....2..0..0..0..0....1..0..2..2..0....2..0..0..0..0
..1..0..2..2..0....1..0..0..2..2....2..0..1..1..0....1..0..0..0..2
..2..0..1..1..0....1..2..2..1..2....2..0..0..0..0....1..2..2..0..1
..1..0..0..0..0....2..1..1..0..0....1..2..2..0..0....2..1..1..0..2

Crossrefs

Row 5 of A239030.

Sequence in context: A293884 A121159 A358232 * A254823 A134968 A238419

Adjacent sequences: A239029 A239030 A239031 * A239033 A239034 A239035

Keyword

nonn

Author

R. H. Hardin, Mar 09 2014

Status

approved