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 A140487 #5 Sep 16 2015 13:12:43
%S A140487 3,7,10,14,18,23,26,30,37,40,46,50,54,59,62,66,71,74,78,83,86,90,97,
%T A140487 100,106,110,114,119,122,126,131,134,138,143,146,150,157,160,166,170,
%U A140487 174,179,182,186,191,194,198,203,206,210,218,222,227,230,234,239,242,246
%N A140487 Trajectory of 3 under repeated application of the map: n -> n + second-smallest number that does not divide n.
%t A140487 a = {3, 7}; Do[AppendTo[a, a[[ -1]] + Select[Range[a[[ -1]]], Mod[a[[ -1]], # ] > 0 &][[2]]], {60}]; a (* _Stefan Steinerberger_, Jul 01 2008 *)
%Y A140487 Cf. A140485-A140489.
%K A140487 nonn
%O A140487 1,1
%A A140487 _Eric Angelini_, Jun 25 2008
%E A140487 More terms from _Stefan Steinerberger_, Jul 01 2008