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 A121894 #7 Jan 11 2022 12:33:25
%S A121894 0,2,8,34,177,1131
%N A121894 Van der Waerden numbers: A005346(n) - 1.
%C A121894 The maximum length of a string of 0's and 1's with no n-length "decimated substring" being all 0's or all 1's. A decimated substring is defined to be any subset {x_a, x_(a+p), x_(a+2p), x_(a+3p), ...} for any appropriate a, p.
%C A121894 Some authors prefer this version to A005346.
%e A121894 a(3) = 8 because 00110011 is the maximal string for n=3: appending 1 gives ......111 and appending 0 gives 0...0...0. No other starting string improves on this.
%Y A121894 Cf. A005346.
%K A121894 nonn,more
%O A121894 1,2
%A A121894 _James Dow Allen_, Sep 01 2006
%E A121894 Term a(6) (using A005346) from _Joerg Arndt_, Jun 06 2016