%I #4 May 07 2017 06:40:41
%S 1,4,6,9,14,20,23,25,30,33,49,56,60,248,270,280,302,385,474,479
%N The list of x-coordinates for which nonempty columns arise in the set arising from {(1, 0),(2, 0),(0, 1)}, the classical Ulam sequence on the x-axis augmented by a vector in the orthogonal direction.
%H Noah Kravitz, Stefan Steinerberger, <a href="https://arxiv.org/abs/1705.01883">Ulam Sequences and Ulam Sets</a>, arXiv:1705.01883 [math.CO], 2017.
%Y Cf. A002858.
%K nonn,more
%O 1,2
%A _Michel Marcus_, May 05 2017