The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A332042 Number of integers whose Dedekind psi function (A001615) values are n. 2
 1, 0, 1, 1, 0, 2, 0, 1, 0, 0, 0, 4, 0, 1, 0, 0, 0, 2, 0, 1, 0, 0, 0, 5, 0, 0, 0, 0, 0, 2, 0, 2, 0, 0, 0, 4, 0, 1, 0, 0, 0, 2, 0, 1, 0, 0, 0, 6, 0, 0, 0, 0, 0, 2, 0, 2, 0, 0, 0, 2, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 9, 0, 1, 0, 0, 0, 0, 0, 2, 0, 0, 0, 3, 0, 0, 0 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,6 LINKS Amiram Eldar, Table of n, a(n) for n = 1..10000 EXAMPLE a(6) = 2 since there are 2 solutions to psi(x) = 6: 4 and 5. MATHEMATICA psi[1] = 1; psi[n_] := n * Times @@ (1 + 1/Transpose[FactorInteger[n]][[1]]); m = 100; v = Table[0, {m}]; Do[i = psi[k]; If[i <= m, v[[i]]++], {k, 1, m}]; v CROSSREFS Cf. A001615, A054973, A063974, A332036, A332038, A332040. Sequence in context: A124304 A165408 A186733 * A171368 A322353 A133988 Adjacent sequences:  A332039 A332040 A332041 * A332043 A332044 A332045 KEYWORD nonn AUTHOR Amiram Eldar, Feb 05 2020 STATUS approved

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

Last modified July 25 09:49 EDT 2021. Contains 346289 sequences. (Running on oeis4.)