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A235241 Number of (n+1) X (1+1) 0..7 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
210, 906, 3746, 16150, 66874, 288510, 1195458, 5161934, 21400266, 92486622, 383623154, 1659369022, 6886195834, 29811968622, 123773981922, 536299705358, 2227615662378, 9660029955390, 40141785286994, 174215753195230 (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) = 4*a(n-1) + 39*a(n-2) - 152*a(n-3) - 441*a(n-4) + 1612*a(n-5) + 1185*a(n-6) - 3128*a(n-7) - 782*a(n-8).

Empirical g.f.: 2*x*(105 + 33*x - 4034*x^2 - 1124*x^3 + 43251*x^4 + 10791*x^5 - 84602*x^6 - 20036*x^7) / ((1 - 4*x - x^2)*(1 - 17*x^2)*(1 - 21*x^2 + 46*x^4)). - Colin Barker, Oct 17 2018

EXAMPLE

Some solutions for n=4:

..4..1....0..1....3..7....5..7....4..6....6..2....5..6....4..7....4..2....4..2

..1..4....5..0....6..4....7..3....5..1....1..3....7..2....5..2....3..7....3..7

..3..0....6..7....3..7....4..6....2..4....4..0....5..6....2..5....2..0....7..5

..1..4....7..2....2..0....5..1....6..2....2..4....7..2....4..1....3..7....2..6

..3..0....6..7....1..5....0..2....1..3....4..0....0..1....2..5....4..2....4..2

CROSSREFS

Column 1 of A235248.

Sequence in context: A009127 A158559 A235248 * A046302 A217532 A289319

Adjacent sequences:  A235238 A235239 A235240 * A235242 A235243 A235244

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 05 2014

STATUS

approved

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Last modified September 25 11:34 EDT 2021. Contains 347654 sequences. (Running on oeis4.)