

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 2x(i,j).


1



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

1,2


LINKS



FORMULA

Empirical: a(n) = 59*a(n2)  230*a(n4)  2*a(n6) + 32*a(n8) 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



KEYWORD

nonn


AUTHOR



STATUS

approved



