(Translated by https://www.hiragana.jp/)
# Greetings from The On-Line Encyclopedia of Integer Sequences! http://oeis.org/ Search: id:a238721 Showing 1-1 of 1 %I A238721 #11 Sep 30 2023 13:08:16 %S A238721 4,10,40,86,336,704,2704,5660,21504,45176,170464,359400,1350272, %T A238721 2854496,10694912,22650672,84716224,179637056,671110848,1424180800, %U A238721 5316817088,11288673952,42124029504,89466980000,333750473152,708999096096,2644373950784,5618300601952 %N A238721 Number of n X 3 0..2 arrays with no element equal to the sum modulo 3 of elements to its left or elements above it. %H A238721 R. H. Hardin, Table of n, a(n) for n = 1..210 %F A238721 Empirical: a(n) = 17*a(n-2) -96*a(n-4) +210*a(n-6) -152*a(n-8). %e A238721 Some solutions for n=5: %e A238721 ..1..2..1....2..1..1....2..1..2....2..1..1....1..2..1....1..2..1....2..1..1 %e A238721 ..2..1..2....1..0..2....1..2..1....1..2..2....2..0..0....2..0..0....1..2..2 %e A238721 ..1..2..1....2..0..1....1..2..2....1..2..2....2..0..0....1..0..2....2..1..1 %e A238721 ..2..0..0....1..0..2....2..0..1....2..1..1....1..0..2....2..0..1....1..0..2 %e A238721 ..2..1..2....1..2..1....2..1..2....1..2..1....2..0..1....2..1..2....1..0..2 %Y A238721 Column 3 of A238726. %K A238721 nonn %O A238721 1,1 %A A238721 _R. H. Hardin_, Mar 03 2014 # Content is available under The OEIS End-User License Agreement: http://oeis.org/LICENSE