A065390 - OEIS

%I #16 Jun 20 2018 01:40:20

%S 1,3,7,12,18,28,31,39,42,56,72,91,96,98,168,195,252,280,312,360,372,

%T 392,546,576,744,840,864,992,1092,1170,1344,1512,1680,1860,1872,2016,

%U 2240,2418,2880,3224,3600,3844,4320,4368,4914,5082,5952,6045,6552,7440

%N Peak values reached by A062402 at the sites listed in A065389.

%H Harry J. Smith, <a href="/A065390/b065390.txt">Table of n, a(n) for n = 1..500</a>

%t a=0; s=0; Do[s=DivisorSigma[1, EulerPhi[n]]; If[s>a, a=s; Print[s]], {n, 1, 10000}]

%t (* Second program: *)

%t Union@ FoldList[Max, Array[DivisorSigma[1, EulerPhi[#]] &, 2200]] (* _Michael De Vlieger_, Jun 19 2018 *)

%o (PARI) { n=r=0; for (m=1, 10^9, x=sigma(eulerphi(m)); if (x > r, r=x; write("b065390.txt", n++, " ", x); if (n==500, return)) ) } \\ _Harry J. Smith_, Oct 18 2009

%Y Cf. A062402, A000203, A000010, A065389, A065391, A065392, A065393, A065394.

%K nonn

%O 1,2

%A _Labos Elemer_, Nov 05 2001