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 A267468 #7 Feb 05 2018 09:35:52 %S A267468 6,36,201,1096,5921,31880,171601,925176,5002641,27155800,148092161, %T A267468 811801256,4475004961,24813260520,138416411121,776822970136, %U A267468 4385905536881,24907563562040,142244725848481,816667390335816 %N A267468 Number of length-n 0..5 arrays with no following elements larger than the first repeated value. %C A267468 Column 5 of A267471. %H A267468 R. H. Hardin, <a href="/A267468/b267468.txt">Table of n, a(n) for n = 1..210</a> %F A267468 Empirical: a(n) = 26*a(n-1) -280*a(n-2) +1610*a(n-3) -5299*a(n-4) +9884*a(n-5) -9540*a(n-6) +3600*a(n-7). %F A267468 Conjectures from _Colin Barker_, Feb 05 2018: (Start) %F A267468 G.f.: x*(6 - 120*x + 945*x^2 - 3710*x^3 + 7539*x^4 - 7336*x^5 + 2556*x^6) / ((1 - x)*(1 - 2*x)*(1 - 3*x)*(1 - 4*x)*(1 - 5*x)^2*(1 - 6*x)). %F A267468 a(n) = (-75 - 25*2^(1+n) - 50*3^n + 25*2^(1+n)*3^n - 75*4^n + 413*5^n + 12*5^n*n) / 300. %F A267468 (End) %e A267468 Some solutions for n=7: %e A267468 ..2....1....0....4....3....5....2....0....3....3....4....4....0....4....1....3 %e A267468 ..0....3....3....1....1....0....0....4....0....3....3....3....3....4....4....1 %e A267468 ..4....2....4....2....2....1....4....1....3....1....0....5....1....0....5....2 %e A267468 ..0....4....1....3....0....5....0....5....0....0....3....1....2....0....2....1 %e A267468 ..3....0....5....2....4....4....2....0....3....0....2....0....5....3....0....4 %e A267468 ..4....2....3....2....4....1....5....4....2....3....0....1....5....2....4....3 %e A267468 ..0....4....0....1....0....3....2....3....1....2....3....0....4....1....4....5 %Y A267468 Cf. A267471. %K A267468 nonn %O A267468 1,1 %A A267468 _R. H. Hardin_, Jan 15 2016