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A235087 T(n,k)=Number of (n+1)X(k+1) 0..4 arrays with every 2X2 subblock having its diagonal sum differing from its antidiagonal sum by 4, with no adjacent elements equal (constant stress tilted 1X1 tilings) 9
38, 90, 90, 202, 198, 202, 478, 418, 418, 478, 1078, 930, 830, 930, 1078, 2554, 2002, 1758, 1758, 2002, 2554, 5786, 4514, 3610, 3558, 3610, 4514, 5786, 13726, 9838, 7810, 7046, 7046, 7810, 9838, 13726, 31238, 22402, 16390, 14702, 13446, 14702, 16390 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Table starts

....38.....90....202....478...1078...2554....5786...13726...31238....74202

....90....198....418....930...2002...4514....9838...22402...49294...113086

...202....418....830...1758...3610...7810...16390...36014...76770...170682

...478....930...1758...3558...7046..14702...29970...63862..132746...287122

..1078...2002...3610...7046..13446..27218...53882..111782..226726...478402

..2554...4514...7810..14702..27218..53590..103702..210318..418838...866298

..5786...9838..16390..29970..53882.103702..196302..390578..764386..1553646

.13726..22402..36014..63862.111782.210318..390578..763814.1474106..2953922

.31238..49294..76770.132746.226726.418838..764386.1474106.2809478..5563846

.74202.113086.170682.287122.478402.866298.1553646.2953922.5563846.10902494

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..446

FORMULA

Empirical for column k (k=4..7 recurrence works for k=1..3 also; apparently all rows and columns satisfy the same order 16 recurrence):

k=1: a(n) = 2*a(n-1) +6*a(n-2) -10*a(n-3) -5*a(n-4)

k=2: [order 10]

k=3: [order 15]

k=4..7: [same order 16 recurrence]

EXAMPLE

Some solutions for n=5 k=4

..0..2..1..2..0....2..4..2..4..1....1..4..2..3..0....1..3..0..3..0

..3..1..4..1..3....4..2..4..2..3....3..2..4..1..2....2..0..1..0..1

..2..4..3..4..2....1..3..1..3..0....1..4..2..3..0....1..3..0..3..0

..3..1..4..1..3....2..0..2..0..1....3..2..4..1..2....4..2..3..2..3

..1..3..2..3..1....1..3..1..3..0....1..4..2..3..0....1..3..0..3..0

..3..1..4..1..3....3..1..3..1..2....3..2..4..1..2....2..0..1..0..1

CROSSREFS

Sequence in context: A044557 A014716 A137028 * A235080 A218331 A124141

Adjacent sequences:  A235084 A235085 A235086 * A235088 A235089 A235090

KEYWORD

nonn,tabl

AUTHOR

R. H. Hardin, Jan 03 2014

STATUS

approved

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Last modified May 9 12:48 EDT 2021. Contains 343740 sequences. (Running on oeis4.)