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 A248839 #6 Jul 23 2025 11:47:10 %S A248839 2,6,24,120,720,5038,40260,361636,3606044,39517182,472002456, %T A248839 6102356222,84896359836,1264499036118,20075760897736,338430468325576, %U A248839 6037037185793372,113608224705704476,2249252806749536964 %N A248839 Number of length n arrays x(i), i=1..n with x(i) in 0..i and no value appearing more than 5 times. %C A248839 Column 5 of A248842 %H A248839 R. H. Hardin, <a href="/A248839/b248839.txt">Table of n, a(n) for n = 1..136</a> %e A248839 Some solutions for n=6 %e A248839 ..1....1....0....1....0....1....1....1....0....0....0....1....1....0....0....1 %e A248839 ..2....2....2....2....2....1....1....0....2....1....2....2....1....2....2....0 %e A248839 ..3....3....0....2....1....3....0....1....0....0....1....0....2....3....0....0 %e A248839 ..2....1....2....1....0....4....0....3....0....2....1....1....3....2....1....4 %e A248839 ..1....4....4....5....1....2....2....2....5....0....4....4....5....2....0....3 %e A248839 ..0....0....2....2....5....3....4....0....5....4....1....4....0....0....5....6 %K A248839 nonn %O A248839 1,1 %A A248839 _R. H. Hardin_, Oct 15 2014