A203981 Number of (n+1) X 6 0..2 arrays with no 2 X 2 subblock having equal diagonal elements or equal antidiagonal elements, and new values 0..2 introduced in row major order.

1536, 31104, 629856, 13071456, 271918944, 5671161216, 118333620576, 2469841766784, 51553851826176, 1076137623724896, 22463572543638624, 468912308350736736, 9788249148960940416, 204323642334833818464

Offset

1,1

Comments

Column 5 of A203984.

Links

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

Formula

Empirical: a(n) = 25*a(n-1) - 45*a(n-2) - 963*a(n-3) + 2025*a(n-4) + 3645*a(n-5) - 6561*a(n-6).

Empirical g.f.: 96*x*(16 - 76*x - 819*x^2 + 2124*x^3 + 3321*x^4 - 6561*x^5) / ((1 - 25*x + 90*x^2 - 81*x^3)*(1 - 45*x^2 - 81*x^3)). - Colin Barker, Jun 06 2018

Example

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

Crossrefs

Cf. A203984.

Sequence in context: A179692 A105923 A229507 * A188788 A170793 A224068

Adjacent sequences: A203978 A203979 A203980 * A203982 A203983 A203984

Keyword

nonn

Author

R. H. Hardin, Jan 09 2012

Status

approved