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 A206457 #7 Dec 15 2023 20:27:50
%S A206457 5,216,4048,78050,1679508,40353460,1073741632,31381059366,
%T A206457 999999999700,34522712143568,1283918464548432,51185893014090250,
%U A206457 2177953337809370548,98526125335693358700,4722366482869645212928,239072435685151324846286
%N A206457 Number of 0..n arrays of length n+3 avoiding the consecutive pattern 0..n.
%C A206457 Subdiagonal 3 of A206455.
%H A206457 R. H. Hardin, <a href="/A206457/b206457.txt">Table of n, a(n) for n = 1..210</a>
%F A206457 Empirical: a(n) = Sum_{i=0..floor((n+3)/(n+1))} ((-1)^i*(n+1)^((n+3) -(n+1)*i)*binomial((n+3)-n*i,i)).
%Y A206457 Cf. A206455.
%K A206457 nonn
%O A206457 1,1
%A A206457 _R. H. Hardin_, Feb 07 2012