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 A248837 #8 Jul 23 2025 11:46:57 %S A248837 2,6,24,118,686,4598,34872,295044,2753958,28103804,311216626, %T A248837 3716341042,47597786154,650812077852,9461423560788,145724617925326, %U A248837 2370293673319292,40600119927220706,730458115445479734,13772063820971722638 %N A248837 Number of length n arrays x(i), i=1..n with x(i) in 0..i and no value appearing more than 3 times. %C A248837 Column 3 of A248842. %C A248837 Essentially the same as A135106. - _Georg Fischer_, Oct 23 2018 %H A248837 R. H. Hardin, <a href="/A248837/b248837.txt">Table of n, a(n) for n = 1..210</a> %e A248837 Some solutions for n=6 %e A248837 ..0....1....0....1....0....0....1....1....1....0....0....0....0....0....0....1 %e A248837 ..2....1....0....2....1....1....1....1....1....1....1....0....0....0....1....1 %e A248837 ..2....0....0....0....1....1....2....2....0....3....0....2....3....3....2....2 %e A248837 ..1....0....3....0....0....1....4....4....1....0....1....1....2....4....4....1 %e A248837 ..5....0....2....2....3....4....5....2....2....4....4....0....1....0....5....5 %e A248837 ..3....5....3....1....5....2....5....2....5....0....2....5....0....2....0....6 %K A248837 nonn %O A248837 1,1 %A A248837 _R. H. Hardin_, Oct 15 2014