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A235232 Number of (n+1) X (1+1) 0..6 arrays with every 2 X 2 subblock having its diagonal sum differing from its antidiagonal sum by 6, with no adjacent elements equal (constant stress tilted 1 X 1 tilings). 1
120, 420, 1328, 4652, 14944, 52468, 170864, 601100, 1980544, 6979348, 23223440, 81953324, 274931488, 971325748, 3280518320, 11600884556, 39397352128, 139427487316, 475663660496, 1684432450412, 5768254899040, 20437259824756 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

FORMULA

Empirical: a(n) = 3*a(n-1) + 23*a(n-2) - 63*a(n-3) - 153*a(n-4) + 333*a(n-5) + 249*a(n-6) - 81*a(n-7) - 54*a(n-8).

Empirical g.f.: 4*x*(30 + 15*x - 673*x^2 - 358*x^3 + 3816*x^4 + 2151*x^5 - 933*x^6 - 528*x^7) / ((1 - 3*x)*(1 + 3*x)*(1 - 3*x - 2*x^2)*(1 - 12*x^2 + 3*x^4)). - Colin Barker, Oct 17 2018

EXAMPLE

Some solutions for n=4:

..2..0....2..1....2..4....3..0....1..3....4..1....3..6....4..1....5..0....2..5

..1..5....0..5....6..2....2..5....4..0....0..3....5..2....3..6....4..5....4..1

..3..1....1..0....3..5....6..3....1..3....3..0....0..3....5..2....6..1....0..3

..0..4....0..5....5..1....3..6....4..0....1..4....4..1....2..5....2..3....3..0

..2..0....3..2....4..6....4..1....0..2....5..2....3..6....5..2....5..0....1..4

CROSSREFS

Column 1 of A235239.

Sequence in context: A307933 A235239 A337469 * A304284 A167562 A033697

Adjacent sequences:  A235229 A235230 A235231 * A235233 A235234 A235235

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 05 2014

STATUS

approved

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Last modified June 16 20:32 EDT 2021. Contains 345069 sequences. (Running on oeis4.)