cp's OEIS Frontend

A208303 Number of 3 X n nonnegative integer arrays with new values 0 upwards introduced in row major order and no element equal to any horizontal or antidiagonal neighbor (colorings ignoring permutations of colors).

%I A208303 #7 May 18 2020 19:56:36
%S A208303 1,5,52,2906,373780,87852626,33093356640,18383354934430,
%T A208303 14216420560211868,14670987603972303070,19558496205580909812744,
%U A208303 32828323774419481541135978,67939294184199439807451132308,170381709310740181061939305134514,510275358861788633812686061715278224
%N A208303 Number of 3 X n nonnegative integer arrays with new values 0 upwards introduced in row major order and no element equal to any horizontal or antidiagonal neighbor (colorings ignoring permutations of colors).
%H A208303 Andrew Howroyd, <a href="/A208303/b208303.txt">Table of n, a(n) for n = 0..100</a>
%e A208303 Some solutions for n=4:
%e A208303 ..0..1..2..0....0..1..0..1....0..1..0..2....0..1..0..1....0..1..2..0
%e A208303 ..2..1..2..0....0..1..0..1....3..1..0..2....0..1..0..1....3..0..1..0
%e A208303 ..0..3..1..0....0..1..2..1....0..1..0..1....2..1..2..0....1..0..3..0
%Y A208303 Row 3 of A208301.
%K A208303 nonn
%O A208303 0,2
%A A208303 _R. H. Hardin_, Feb 25 2012
%E A208303 a(0)=1 prepended and terms a(10) and beyond from _Andrew Howroyd_, May 18 2020