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 A204702 #8 Jul 22 2025 18:14:41 %S A204702 30,5400,362020,29846373,2389914827,192759130113,15521787839696, %T A204702 1250634888842984,100749784360671667,8116764740949394264, %U A204702 653904134820543785397,52680223968250151357189,4244049256144093743987455 %N A204702 Number of nX5 0..2 arrays with no occurrence of three equal elements in a row horizontally, vertically or nw-to-se diagonally, and new values 0..2 introduced in row major order. %C A204702 Column 5 of A204705 %H A204702 R. H. Hardin, <a href="/A204702/b204702.txt">Table of n, a(n) for n = 1..210</a> %e A204702 Some solutions for n=5 %e A204702 ..0..0..1..2..0....0..0..1..2..2....0..0..1..0..0....0..0..1..2..0 %e A204702 ..1..2..1..2..1....2..1..2..1..1....1..2..1..0..0....1..1..2..0..2 %e A204702 ..2..1..0..0..1....1..2..1..1..2....2..0..0..2..1....2..2..1..2..2 %e A204702 ..1..1..2..1..2....1..1..0..2..2....2..1..1..2..1....2..1..0..0..1 %e A204702 ..2..2..1..1..0....2..2..0..1..0....0..0..1..0..2....0..1..0..1..0 %K A204702 nonn %O A204702 1,1 %A A204702 _R. H. Hardin_ Jan 18 2012