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 A072416 #11 Mar 12 2015 19:15:06
%S A072416 2,13,49,149,373,835,1727,3383,6341,11419,19966,34067,56967,93578,
%T A072416 151313,241281,379934,591413,910879,1389289,2099905,3147743,4682362,
%U A072416 6914234,10141072,14779023,21408820,30837491,44179913,62974570,89329823
%N A072416 a(1) = 2; a(n) = half of the a(n-1)-th even nontotient number.
%F A072416 a(5) = 373 = 746/2, where 746 is the a(4) = 149th term in A005277.
%t A072416 a = Table[0, {10^6}]; Do[b = EulerPhi[n]/2; If[b < 10^6 + 1, a[[b]] = 1], {n, 1, 2 10^7}]; b = Select[ Range[10^6], a[[ # ]] == 0 &]; c = 2; Do[ Print[c]; c = b[[c]], {n, 0, 17}]
%Y A072416 Cf. A006508, A071255, A005277, A072415.
%K A072416 nonn
%O A072416 1,1
%A A072416 _Labos Elemer_, Jun 17 2002
%E A072416 Edited by _Robert G. Wilson v_, Jun 20 2002
%E A072416 a(18)-a(31) from _Donovan Johnson_, Oct 29 2010