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 A211557 #6 Jun 02 2025 07:47:23
%S A211557 1,11,81,512,3046,17866,106133,649045,4125023,27378716,190102160,
%T A211557 1380567060,10472967693,82843346443,682012236077,5832548494812,
%U A211557 51723577104638,474868072764550,4506710508270721,44151990164554541
%N A211557 Number of nonnegative integer arrays of length n+3 with new values 0 upwards introduced in order, and containing the value 3.
%C A211557 Column 4 of A211561
%H A211557 R. H. Hardin, <a href="/A211557/b211557.txt">Table of n, a(n) for n = 1..210</a>
%F A211557 Empirical: a(n) = sum{j in 4..n+3}stirling2(n+3,j)
%e A211557 Some solutions for n=5
%e A211557 ..0....0....0....0....0....0....0....0....0....0....0....0....0....0....0....0
%e A211557 ..1....1....0....1....1....0....1....1....1....0....1....1....1....1....1....1
%e A211557 ..0....0....0....2....2....1....2....2....1....1....2....2....1....2....2....0
%e A211557 ..2....2....1....3....3....2....0....0....2....2....0....0....2....3....0....2
%e A211557 ..0....1....2....0....1....0....3....2....2....2....3....0....3....2....3....3
%e A211557 ..2....0....1....1....3....1....1....3....3....3....4....1....1....2....2....2
%e A211557 ..3....2....3....4....4....0....0....2....0....0....2....0....2....1....3....0
%e A211557 ..0....3....0....4....2....3....1....3....4....1....3....3....0....0....2....3
%K A211557 nonn
%O A211557 1,2
%A A211557 _R. H. Hardin_ Apr 15 2012