A230736 Number of (n+3)X(2+3) 0..2 black square subarrays x(i,j) with each element diagonally or antidiagonally next to at least one element with value (x(i,j)+1) mod 3, and upper left element zero.
8, 66, 244, 2016, 6576, 54138, 173428, 1427040, 4558536, 37506738, 119758148, 985334832, 3145930352, 25883741898, 82639468964, 679931791152, 2170826159272, 17860880147874, 57024624645332, 469180811419968, 1497958570841456
Offset: 1
Keywords
Examples
Some solutions for n=3 ..x..0..x..0..x....x..0..x..1..x....x..0..x..2..x....x..0..x..0..x ..2..x..1..x..1....1..x..2..x..0....2..x..1..x..0....2..x..1..x..2 ..x..1..x..2..x....x..2..x..1..x....x..1..x..1..x....x..2..x..2..x ..0..x..0..x..1....1..x..0..x..0....0..x..2..x..0....0..x..0..x..1 ..x..0..x..2..x....x..2..x..2..x....x..0..x..2..x....x..1..x..0..x ..2..x..1..x..1....1..x..1..x..1....2..x..1..x..1....0..x..2..x..2
Links
- R. H. Hardin, Table of n, a(n) for n = 1..210
Formula
Empirical: a(n) = 31*a(n-2) -126*a(n-4) +42*a(n-6) +79*a(n-8) -a(n-10) +8*a(n-12)
Comments