A230659 - OEIS

%I #8 Sep 22 2018 10:52:46

%S 0,15,135,531,8613,28161,477279,1539207,26178201,84335553,1434726783,

%T 4621740687,78627215025,253283346081,4308981442911,13880597644287,

%U 236143613924865,760693546670625,12941296146524511,41688023124390687

%N 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).

%H R. H. Hardin, <a href="/A230659/b230659.txt">Table of n, a(n) for n = 1..210</a>

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

%F 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

%e Some solutions for n=5:

%e ..x..0..x..0..x....x..0..x..1..x....x..2..x..0..x....x..0..x..2..x

%e ..2..x..0..x..2....2..x..2..x..1....0..x..0..x..2....2..x..2..x..0

%e ..x..2..x..2..x....x..2..x..1..x....x..2..x..0..x....x..2..x..2..x

%e ..0..x..2..x..1....0..x..1..x..0....2..x..0..x..1....0..x..0..x..1

%e ..x..0..x..1..x....x..1..x..2..x....x..0..x..1..x....x..2..x..1..x

%Y Column 5 of A230661.

%K nonn

%O 1,2

%A _R. H. Hardin_, Oct 27 2013