A268902 Number of n X 6 0..2 arrays with some element plus some horizontally or antidiagonally adjacent neighbor totalling two exactly once.

240, 9720, 299088, 8250912, 214142760, 5344944120, 129834259704, 3091414865040, 72488795124312, 1679265104747616, 38520989302343760, 876481043382776664, 19806871824479466648, 444994736265664134120, 9947337685046673808176

Offset

1,1

Links

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

Formula

Empirical: a(n) = 50*a(n-1) - 805*a(n-2) + 4662*a(n-3) - 12150*a(n-4) + 14580*a(n-5) - 6561*a(n-6).

Empirical g.f.: 24*x*(10 - 95*x + 262*x^2 + 93*x^3 - 1485*x^4 + 1701*x^5) / (1 - 25*x + 90*x^2 - 81*x^3)^2. - Colin Barker, Jan 16 2019

Example

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

Crossrefs

Column 6 of A268904.

Sequence in context: A251434 A187167 A282227 * A232994 A023906 A292883

Adjacent sequences: A268899 A268900 A268901 * A268903 A268904 A268905

Keyword

nonn

Author

R. H. Hardin, Feb 15 2016

Status

approved