This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A276303 #4 Aug 28 2016 08:30:47 %S A276303 122,250,3437,34865,442001,4988145,59728757,693817033,8184858377, %T A276303 95798120125,1125757112093,13202147428061,154987529747569, %U A276303 1818521601523949,21343104642406881,250459145656655937 %N A276303 Number of 6Xn 0..2 arrays with no element equal to any value at offset (-2,-1) (-1,1) or (0,-1) and new values introduced in order 0..2. %C A276303 Row 6 of A276299. %H A276303 R. H. Hardin, <a href="/A276303/b276303.txt">Table of n, a(n) for n = 1..210</a> %F A276303 Empirical: a(n) = 3*a(n-1) +78*a(n-2) +250*a(n-3) +558*a(n-4) -937*a(n-5) -4256*a(n-6) -7991*a(n-7) -3472*a(n-8) +31381*a(n-9) -11144*a(n-10) +42683*a(n-11) -198936*a(n-12) +231086*a(n-13) -131301*a(n-14) +70502*a(n-15) -27827*a(n-16) +159651*a(n-17) -217780*a(n-18) +120250*a(n-19) -55920*a(n-20) -17125*a(n-21) +26805*a(n-22) -25487*a(n-23) +30226*a(n-24) -15183*a(n-25) +5503*a(n-26) -1930*a(n-27) +371*a(n-28) -65*a(n-29) +8*a(n-30) for n>32 %e A276303 Some solutions for n=4 %e A276303 ..0..1..2..0. .0..1..0..2. .0..1..2..1. .0..1..2..1. .0..1..0..1 %e A276303 ..2..1..2..0. .0..2..0..1. .0..1..2..1. .0..1..0..1. .2..1..0..1 %e A276303 ..2..1..2..1. .1..2..0..1. .2..1..0..1. .0..1..2..1. .2..1..0..1 %e A276303 ..0..1..0..1. .0..2..0..1. .0..1..0..1. .2..1..2..1. .0..1..0..2 %e A276303 ..0..1..0..1. .1..2..0..2. .0..1..0..1. .2..1..2..0. .0..1..0..1 %e A276303 ..0..1..2..1. .0..1..0..1. .0..2..0..2. .2..0..2..1. .2..1..0..1 %Y A276303 Cf. A276299. %K A276303 nonn %O A276303 1,1 %A A276303 _R. H. Hardin_, Aug 28 2016