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 A206456 #12 Aug 19 2025 15:27:58
%S A206456 4,75,1016,15615,279924,5764787,134217712,3486784383,99999999980,
%T A206456 3138428376699,106993205379048,3937376385699263,155568095557812196,
%U A206456 6568408355712890595,295147905179352825824,14063084452067724990975,708235345355337676357596,37589973457545958193355563
%N A206456 Number of 0..n arrays of length n+2 avoiding the consecutive pattern 0..n.
%H A206456 R. H. Hardin, <a href="/A206456/b206456.txt">Table of n, a(n) for n = 1..210</a>
%F A206456 Empirical: a(n) = Sum_{i=0..floor((n+2)/(n+1))} ((-1)^i*(n+1)^((n+2) -(n+1)*i)*binomial((n+2) -n*i,i)).
%Y A206456 Subdiagonal 2 of A206455.
%K A206456 nonn
%O A206456 1,1
%A A206456 _R. H. Hardin_, Feb 07 2012