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%I #17 Oct 25 2017 02:52:32
%S 1,2,4,6,8,12,16,20,24,32,36,40,48,64,72,80,96,120,128,144,160,176,
%T 192,224,240,288,320,336,384,432,480,576,672,720,768,864,960,1056,
%U 1152,1280,1296,1344,1440,1536,1680,1728,1920,2112,2208,2304,2400,2592,2688
%N Indices of the left-to-right maxima in A057635.
%C A number m belongs to this sequence iff A057635(k) < A057635(m) for all k<m.
%C Indices of records in A057635(n), the maximal m with phi(m)=n.
%C The Alekseyev link in A131883 establishes the following explicit relationship between A131883, A036912 and A057635. Namely, for t belonging to A036912, we have t=A131883(A057635(t)-1). In other words, A036912(n) = A131883(A057635(A036912(n))-1) for all n.
%H T. D. Noe, <a href="/A036912/b036912.txt">Table of n, a(n) for n = 1..5000</a>
%F a(n) = A000010(A036913(n)). - _Max Alekseyev_, Nov 07 2007
%t Block[{nn = 10^6, s, t, u}, s = PositionIndex@ Array[EulerPhi, nn]; t = ConstantArray[0, nn]; u = Take[ReplacePart[t, Map[# -> Last@ Lookup[s, #] &, Keys@ s]], 10^(Log10[nn] - 2)]; Map[FirstPosition[u, #][[1]] &, Union@ FoldList[Max, u]]] (* _Michael De Vlieger_, Oct 24 2017 *)
%Y Cf. A057635, A000010, A006511, A036913, A132154, A131883.
%K nonn
%O 1,2
%A _David W. Wilson_
%E More precise definition from _Max Alekseyev_, Nov 07 2007
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