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 A269140 #6 Feb 20 2016 06:47:08 %S A269140 756,59916,3924212,240647068,14197016484,815458664276,45920055321732, %T A269140 2546667557472940,139535357045338964,7570570235882777884, %U A269140 407418697407850105348,21776207050517593512788,1157149832292866826527492 %N A269140 Number of nX5 0..3 arrays with some element plus some horizontally, antidiagonally or vertically adjacent neighbor totalling three no more than once. %C A269140 Column 5 of A269143. %H A269140 R. H. Hardin, <a href="/A269140/b269140.txt">Table of n, a(n) for n = 1..210</a> %F A269140 Empirical: a(n) = 134*a(n-1) -6403*a(n-2) +137212*a(n-3) -1537987*a(n-4) +10006762*a(n-5) -41364815*a(n-6) +107588656*a(n-7) -111196320*a(n-8) -399050332*a(n-9) +2108507944*a(n-10) -4098003684*a(n-11) +445179883*a(n-12) +18009896226*a(n-13) -42207232033*a(n-14) +12581717548*a(n-15) +122544940860*a(n-16) -203283873760*a(n-17) -79843687188*a(n-18) +508551706160*a(n-19) -240288894385*a(n-20) -648319426210*a(n-21) +662670918703*a(n-22) +480938145704*a(n-23) -858808887300*a(n-24) -176689259732*a(n-25) +734283407564*a(n-26) -39751157620*a(n-27) -450104705459*a(n-28) +101139044518*a(n-29) +200718146529*a(n-30) -72282159428*a(n-31) -63674380919*a(n-32) +31546829386*a(n-33) +13183985923*a(n-34) -9057688788*a(n-35) -1275648164*a(n-36) +1571020336*a(n-37) -67398016*a(n-38) -125671104*a(n-39) +17151168*a(n-40) +3564288*a(n-41) -665856*a(n-42) for n>45 %e A269140 Some solutions for n=2 %e A269140 ..0..1..3..3..3. .2..3..2..3..2. .3..1..1..3..2. .2..3..1..0..0 %e A269140 ..1..3..2..2..3. .0..2..3..3..2. .1..0..2..3..2. .1..3..1..0..0 %Y A269140 Cf. A269143. %K A269140 nonn %O A269140 1,1 %A A269140 _R. H. Hardin_, Feb 20 2016