A266131 T(n,k) = Number of n X k integer arrays with each element equal to the number of horizontal, diagonal and antidiagonal neighbors exactly one smaller than itself.
1, 3, 1, 4, 9, 1, 5, 25, 20, 1, 9, 49, 77, 61, 1, 16, 149, 117, 385, 189, 1, 25, 625, 278, 572, 2099, 544, 1, 39, 2141, 1959, 3851, 4336, 9083, 1629, 1, 64, 5433, 11044, 44623, 62104, 19750, 48188, 4973, 1, 105, 17269, 36730, 347576, 1285961, 326145, 102201, 249446
Offset: 1
Examples
Some solutions for n=4, k=4 ..0..0..1..1....0..2..1..2....1..0..2..1....2..1..2..0....0..2..1..0 ..0..2..0..1....0..0..1..2....0..2..0..1....0..1..2..0....0..2..1..1 ..0..0..1..2....0..2..0..2....3..2..1..1....1..0..2..0....0..2..0..2 ..0..2..1..2....0..0..1..1....0..2..1..0....1..1..0..0....0..0..1..1
Links
- R. H. Hardin, Table of n, a(n) for n = 1..97
Formula
Empirical for column k:
k=1: a(n) = a(n-1),
k=2: [order 10],
k=3: [order 26] for n>27,
Empirical for row n:
n=1: a(n) = a(n-1) +a(n-3) +a(n-4),
n=2: [order 17],
n=3: [order 77].
Comments