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 A135415 #17 Feb 16 2025 08:33:07 %S A135415 3,9,27,76 %N A135415 Van der Waerden numbers for 3-arithmetic progressions with n colors. %C A135415 It is known that a(5) > 170. %H A135415 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/vanderWaerdenNumber.html">Van der Waerden numbers</a> %H A135415 Wikipedia, <a href="https://en.wikipedia.org/wiki/Van_der_Waerden_number">Van der Waerden number</a> %Y A135415 Cf. A005346. %K A135415 nonn,hard,more %O A135415 1,1 %A A135415 Hunter Monroe (hmonroe(AT)huntermonroe.com), Feb 17 2008 %E A135415 a(1) prepended by _Jinyuan Wang_, Mar 13 2020