%I #16 Feb 21 2021 06:03:51
%S 3,9,27,76
%N Van der Waerden numbers for 3-arithmetic progressions with n colors.
%C It is known that a(5) > 170.
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/vanderWaerdenNumber.html">Van der Waerden numbers</a>
%H Wikipedia, <a href="https://en.wikipedia.org/wiki/Van_der_Waerden_number">Van der Waerden number</a>
%Y Cf. A005346.
%K nonn,hard,more
%O 1,1
%A Hunter Monroe (hmonroe(AT)huntermonroe.com), Feb 17 2008
%E a(1) prepended by _Jinyuan Wang_, Mar 13 2020