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 A221316 #6 Apr 18 2023 14:45:51 %S A221316 1,2,6,8,19,44,84,212,474,1008,2438,5436,12045,28174,63292,142936, %T A221316 330285,748286,1707460,3930660,8968641,20569786,47335822,108517496, %U A221316 249608726,574843912,1322068800,3046723144,7024972918,16192943826,37371650024 %N A221316 Number of nonnegative integer arrays of length n summing to n without equal adjacent values modulo 3. %C A221316 Column 3 of A221321. %H A221316 R. H. Hardin, <a href="/A221316/b221316.txt">Table of n, a(n) for n = 1..210</a> %e A221316 Some solutions for n=6 %e A221316 ..0....1....1....4....0....0....2....0....0....1....3....1....0....0....0....1 %e A221316 ..1....0....3....0....2....1....1....2....1....0....1....0....1....1....2....0 %e A221316 ..2....1....1....1....1....2....0....1....0....2....0....1....3....0....0....1 %e A221316 ..0....3....0....0....0....1....2....2....2....0....1....2....1....4....2....0 %e A221316 ..1....1....1....1....1....2....1....1....1....1....0....0....0....0....0....1 %e A221316 ..2....0....0....0....2....0....0....0....2....2....1....2....1....1....2....3 %Y A221316 Cf. A221321. %K A221316 nonn %O A221316 1,2 %A A221316 _R. H. Hardin_, Jan 10 2013