login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

Subscript m such that PhiComposite-Harmonic series cd[m]=Sum[1/A000010[A002808(k)],{k,1,m}]>=n.
1

%I #11 Oct 15 2013 22:31:29

%S 2,7,16,31,60,113,205,371,663,1176,2069,3631,6341,11039,19159,33164,

%T 57287,98763,169967,292061,501165,858892,1470334,2514423,4295912,

%U 7333264,12508213,21319360,36312685,61811287,105152840,178787270,303829041,516074615,876190239

%N Subscript m such that PhiComposite-Harmonic series cd[m]=Sum[1/A000010[A002808(k)],{k,1,m}]>=n.

%t c[x_] := FixedPoint[x+PrimePi[ # ]+1&, x] {s=0, s1=0}; Do[s=s+(1/EulerPhi[c[n]]); If[Greater[Floor[s], s1], s1=Floor[s]; Print[{n, Floor[s]}]], {n, 1, 1000000}]

%Y Cf. A004080, A002387, A002808, A000203, A073255, A046024, A074631, A074633, A074468, A074469.

%K hard,nonn

%O 1,1

%A _Labos Elemer_, Sep 05 2002

%E More terms from Lambert Klasen (lambert.klasen(AT)gmx.net), Jul 23 2005

%E a(30)-a(35) from _Donovan Johnson_, Aug 21 2011