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 A242470 #6 Jul 23 2025 11:16:37 %S A242470 4,12,41,159,685,3233,16533,90817,531812,3295779,21456363,145645809, %T A242470 1023308083,7391587656,54563960012,409583330514,3113836080693, %U A242470 23899707589707,184747234605277,1435668152296255,11200152289621048 %N A242470 Number of length n+2 0..7 arrays with no three equal elements in a row and new values 0..7 introduced in 0..7 order. %C A242470 Column 7 of A242472 %H A242470 R. H. Hardin, <a href="/A242470/b242470.txt">Table of n, a(n) for n = 1..210</a> %F A242470 Empirical: a(n) = 22*a(n-1) -168*a(n-2) +440*a(n-3) +421*a(n-4) -2898*a(n-5) -924*a(n-6) +7944*a(n-7) +5931*a(n-8) -6610*a(n-9) -10562*a(n-10) -5040*a(n-11) -840*a(n-12) %e A242470 Some solutions for n=4 %e A242470 ..0....0....0....0....0....0....0....0....0....0....0....0....0....0....0....0 %e A242470 ..0....1....1....0....1....1....1....1....1....1....1....1....1....1....1....1 %e A242470 ..1....2....2....1....2....2....2....2....2....0....2....0....1....1....2....2 %e A242470 ..0....0....3....2....2....0....0....1....2....2....3....1....2....2....0....2 %e A242470 ..2....1....3....2....0....2....3....3....3....0....4....1....0....0....0....1 %e A242470 ..0....0....1....0....0....1....1....4....1....2....4....2....2....3....3....0 %K A242470 nonn %O A242470 1,1 %A A242470 _R. H. Hardin_, May 15 2014