A222778 Number of n X 3 0..6 arrays with no element equal to another at a city block distance of exactly two, and new values 0..6 introduced in row major order.

3, 34, 969, 64752, 5227536, 436214328, 36601614264, 3073970725512, 258205634457816, 21689162608860168, 1821888109561493784, 153038579509053600072, 12855240375043076417496, 1079840187251574876131208

Offset

1,1

Comments

Column 3 of A222779.

Links

R. H. Hardin, Table of n, a(n) for n = 1..25

Formula

Empirical: a(n) = 101*a(n-1) - 1470*a(n-2) + 3528*a(n-3) for n>5.

Empirical g.f.: x*(3 - 269*x + 1945*x^2 + 6279*x^3 - 7938*x^4) / ((1 - 3*x)*(1 - 14*x)*(1 - 84*x)). - Colin Barker, Aug 16 2018

Example

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

Crossrefs

Cf. A222779.

Sequence in context: A222869 A069718 A077144 * A101633 A250093 A054783

Adjacent sequences: A222775 A222776 A222777 * A222779 A222780 A222781

Keyword

nonn

Author

R. H. Hardin, Mar 05 2013

Status

approved