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 A269293 #4 Feb 21 2016 09:30:28 %S A269293 1024,314928,43674876,5306911092,598478857956,64538382287988, %T A269293 6751724437907820,691013309706097812,69557358002931376452, %U A269293 6911040753656957427300,679500524238978108503340 %N A269293 Number of 5Xn 0..3 arrays with some element plus some horizontally or antidiagonally adjacent neighbor totalling three no more than once. %C A269293 Row 5 of A269289. %H A269293 R. H. Hardin, <a href="/A269293/b269293.txt">Table of n, a(n) for n = 1..210</a> %F A269293 Empirical: a(n) = 262*a(n-1) -25913*a(n-2) +1271424*a(n-3) -36373480*a(n-4) +662028380*a(n-5) -8018113210*a(n-6) +65608158980*a(n-7) -356568260410*a(n-8) +1185405035940*a(n-9) -1609856308508*a(n-10) -4162483461884*a(n-11) +23709461283851*a(n-12) -40474763971218*a(n-13) +272846513475*a(n-14) +106799477038956*a(n-15) -171480164894532*a(n-16) +115612142099328*a(n-17) -29562621871104*a(n-18) for n>23 %e A269293 Some solutions for n=2 %e A269293 ..0..1. .0..0. .1..0. .1..3. .1..3. .2..2. .2..0. .0..2. .0..1. .0..0 %e A269293 ..3..3. .0..3. .1..0. .1..1. .2..2. .0..1. .2..3. .0..0. .2..0. .1..0 %e A269293 ..1..0. .1..0. .2..2. .0..2. .3..2. .1..1. .2..2. .2..1. .1..3. .1..3 %e A269293 ..0..0. .0..2. .2..0. .0..3. .3..0. .3..1. .3..2. .3..1. .1..0. .0..0 %e A269293 ..2..2. .2..3. .1..2. .2..3. .0..0. .0..1. .2..1. .1..1. .1..1. .0..0 %Y A269293 Cf. A269289. %K A269293 nonn %O A269293 1,1 %A A269293 _R. H. Hardin_, Feb 21 2016