A230659 Number of n X 5 0..2 black square subarrays x(i,j) with each element diagonally or antidiagonally next to at least one element with value 2-x(i,j).

0, 15, 135, 531, 8613, 28161, 477279, 1539207, 26178201, 84335553, 1434726783, 4621740687, 78627215025, 253283346081, 4308981442911, 13880597644287, 236143613924865, 760693546670625, 12941296146524511, 41688023124390687

Offset

1,2

Links

R. H. Hardin, Table of n, a(n) for n = 1..210

Formula

Empirical: a(n) = 59*a(n-2) - 230*a(n-4) - 2*a(n-6) + 32*a(n-8) for n>10.

Empirical g.f.: 3*x^2*(5 + 45*x - 118*x^2 + 216*x^3 + 94*x^4 + 54*x^5 - 44*x^6 - 16*x^8) / (1 - 59*x^2 + 230*x^4 + 2*x^6 - 32*x^8). - Colin Barker, Sep 22 2018

Example

Some solutions for n=5:
..x..0..x..0..x....x..0..x..1..x....x..2..x..0..x....x..0..x..2..x
..2..x..0..x..2....2..x..2..x..1....0..x..0..x..2....2..x..2..x..0
..x..2..x..2..x....x..2..x..1..x....x..2..x..0..x....x..2..x..2..x
..0..x..2..x..1....0..x..1..x..0....2..x..0..x..1....0..x..0..x..1
..x..0..x..1..x....x..1..x..2..x....x..0..x..1..x....x..2..x..1..x

Crossrefs

Column 5 of A230661.

Sequence in context: A348212 A289421 A201138 * A228583 A027630 A027629

Adjacent sequences: A230656 A230657 A230658 * A230660 A230661 A230662

Keyword

nonn

Author

R. H. Hardin, Oct 27 2013

Status

approved