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