A269897 Number of n X 3 0..6 arrays with some element plus some horizontally or vertically adjacent neighbor totalling six exactly once.

84, 45360, 12377400, 2801265390, 579818225700, 113873466835170, 21603218450171400, 3998999827651729950, 726818744373948859500, 130236638797904930468730, 23073817637719546502490000

Offset

1,1

Links

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

Formula

Empirical: a(n) = 330*a(n-1) - 28773*a(n-2) + 255420*a(n-3) - 599076*a(n-4) for n>5.

Empirical g.f.: 42*x*(2 + 420*x - 4154*x^2 + 9795*x^3 + 1152*x^4) / (1 - 165*x + 774*x^2)^2. - Colin Barker, Jan 29 2019

Example

Some solutions for n=2:
..0..3..1. .2..0..3. .2..1..4. .4..5..0. .5..3..4. .0..4..3. .3..6..4
..4..4..5. .3..6..1. .2..0..2. .3..3..1. .3..6..2. .2..4..4. .4..1..2

Crossrefs

Column 3 of A269902.

Sequence in context: A269933 A184126 A185403 * A184896 A203093 A290274

Adjacent sequences: A269894 A269895 A269896 * A269898 A269899 A269900

Keyword

nonn

Author

R. H. Hardin, Mar 07 2016

Status

approved