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 A275180 #6 May 10 2021 12:18:06 %S A275180 41,256,317,482,1465,4603,14643,46799,149772,479722,1538582,4942028, %T A275180 15891866,51127466,164489244,529125544,1701961499,5474696445, %U A275180 17611978722,56660560468,182287542046,586443173365,1886643497675,6069534405199 %N A275180 Number of n X 5 0..2 arrays with no element equal to any value at offset (-2,-1) (-1,0) or (-1,1) and new values introduced in order 0..2. %C A275180 Column 5 of A275183. %H A275180 R. H. Hardin, <a href="/A275180/b275180.txt">Table of n, a(n) for n = 1..210</a> %F A275180 Empirical: a(n) = 16*a(n-1) -120*a(n-2) +561*a(n-3) -1820*a(n-4) +4313*a(n-5) -7688*a(n-6) +10549*a(n-7) -11473*a(n-8) +10333*a(n-9) -8076*a(n-10) +5538*a(n-11) -3198*a(n-12) +1466*a(n-13) -508*a(n-14) +120*a(n-15) -12*a(n-16) for n > 21. %e A275180 Some solutions for n=4 %e A275180 ..0..1..2..2..0. .0..0..1..2..2. .0..0..1..2..0. .0..1..1..2..2 %e A275180 ..2..0..0..1..2. .2..2..0..0..1. .2..2..0..1..1. .2..2..0..0..1 %e A275180 ..1..1..2..0..1. .0..1..1..2..0. .1..1..2..0..0. .1..1..2..2..0 %e A275180 ..2..0..1..2..2. .2..0..0..1..1. .0..0..1..2..2. .2..0..1..1..1 %Y A275180 Cf. A275183. %K A275180 nonn %O A275180 1,1 %A A275180 _R. H. Hardin_, Jul 19 2016