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A235087 T(n,k) is the number of (n+1) X (k+1) 0..4 arrays with every 2 X 2 subblock having its diagonal sum differing from its antidiagonal sum by 4, with no adjacent elements equal (constant-stress tilted 1 X 1 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 November 26 21:15 EST 2022. Contains 358362 sequences. (Running on oeis4.)