This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A053568 Totients of nontotient numbers. 0
 2, 4, 6, 6, 10, 12, 6, 8, 16, 18, 12, 22, 20, 12, 18, 28, 30, 20, 16, 24, 36, 18, 24, 40, 42, 24, 46, 42, 20, 32, 52, 40, 36, 58, 60, 30, 36, 48, 66, 32, 44, 70, 72, 36, 40, 36, 60, 78, 54, 82, 64, 42, 56, 88, 24, 72, 60, 46, 72, 96, 42, 60, 100, 102, 48, 106 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS See comment at analogous sequence A053474. LINKS FORMULA a(n) = A000010(A007617(n)). EXAMPLE If n=19 then no number x such that phi(x) = n exists; however, phi(19) = 18; n=27 is also a nontotient number whose totient is 18. PROG (PARI) lista(nn) = for (n=1, nn, if (!istotient(n), print1(eulerphi(n), ", "))); \\ Michel Marcus, Nov 20 2017 CROSSREFS Cf. A000010, A007617. Sequence in context: A061228 A070229 A248835 * A037225 A060685 A073353 Adjacent sequences:  A053565 A053566 A053567 * A053569 A053570 A053571 KEYWORD nonn AUTHOR Labos Elemer, Jan 17 2000 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 October 18 22:14 EDT 2019. Contains 328211 sequences. (Running on oeis4.)