The OEIS mourns the passing of Jim Simons and is grateful to the Simons Foundation for its support of research in many branches of science, including the OEIS.
The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A365793 a(n) = number of k <= b(n) such that rad(k) = rad(b(n)), where rad(n) = A007947(n) and b(n) = A286708(n). 2
 5, 8, 6, 10, 11, 6, 8, 14, 5, 15, 16, 8, 11, 18, 5, 7, 12, 20, 21, 8, 7, 11, 14, 23, 18, 9, 24, 15, 6, 9, 25, 8, 5, 26, 8, 9, 13, 8, 6, 14, 18, 29, 19, 26, 11, 30, 19, 12, 8, 31, 10, 20, 32, 6, 32, 11, 16, 10, 33, 5, 10, 17, 22, 6, 8, 8, 13, 35, 28, 36, 8, 14 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Alternatively, position of A126706(n) in the list k*{R(k)} containing m such that A007947(m) = k, where k = A007947(n). LINKS Michael De Vlieger, Table of n, a(n) for n = 1..10000 FORMULA a(n) = A008479(A286708(n)). a(n) > 1 for all n. EXAMPLE a(1) = 5 since rad(b(1)) = rad(36) = 6, and in the sequence k*{R(6)} = 6*{A003586} = {6, 12, 18, 24, 36, ...}, 36 is the 5th term. a(2) = 8 since rad(b(2)) = rad(72) = 6, and 72 is the 8th term in k*{R(6)}. a(3) = 6 since rad(b(3)) = rad(100) = 10, and in the sequence k*{R(10)} = 10*{A003592} = {10, 20, 40, 50, 80, 100, ...}, 100 is the 6th term, etc. MATHEMATICA nn = 4000; f[x_] := f[x] = Times @@ FactorInteger[x][[All, 1]]; t = Select[ Select[Range[nn], Nor[PrimePowerQ[#], SquareFreeQ[#]] &], AllTrue[FactorInteger[#][[All, -1]], # > 1 &] &]; s = Map[f, t]; Map[Function[k, Set[r[k], k*Select[Range[nn/k], Divisible[k, f[#]] &]]], Union@ s]; Array[FirstPosition[r[s[[#]]], t[[#]]][[1]] &, Length[t]] CROSSREFS Cf. A007947, A286708, A365786, A365792. Sequence in context: A346443 A145432 A335565 * A070371 A199444 A005120 Adjacent sequences: A365790 A365791 A365792 * A365794 A365795 A365796 KEYWORD nonn AUTHOR Michael De Vlieger, Sep 22 2023 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified May 27 12:27 EDT 2024. Contains 372858 sequences. (Running on oeis4.)