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!)
 A073462 Number of solutions to phi(x) - pi(x) = n. 2
 6, 8, 5, 9, 3, 3, 6, 6, 1, 5, 5, 3, 3, 5, 3, 4, 6, 1, 5, 7, 5, 2, 4, 2, 1, 5, 5, 1, 4, 2, 2, 7, 3, 4, 4, 4, 2, 5, 1, 4, 1, 6, 4, 5, 3, 2, 4, 2, 3, 6, 1, 6, 3, 6, 3, 1, 1, 2, 5, 4, 3, 3, 4, 2, 0, 4, 3, 4, 3, 1, 2, 6, 4, 4, 0, 5, 5, 4, 2, 6, 4, 3, 2, 5, 5, 1, 1, 9, 1, 3, 1, 4, 4, 3, 3, 2, 4, 4, 3, 2, 4 (list; graph; refs; listen; history; text; internal format)
 OFFSET -1,1 COMMENTS Although Pi takes all values, solutions are not guaranteed since nontotient numbers exist. LINKS FORMULA a(n)=Card[{x; A000010(x)-A000720(x)=n}] EXAMPLE n=-1: 6 solutions = {6,12,18,24,42,60}, a(-1)=6; n=5: for 6 terms of {11,32,34,50,70,150}, phi(#) - pi(#) = 6 holds, so a(5)=6; n=63: no solution was found at x <= 1000000. CROSSREFS Cf. A000010, A000720, A037228, A037171, A073453-A073457, A072530, A072531, A073461, A073461. Sequence in context: A296845 A030644 A319032 * A231095 A201195 A266092 Adjacent sequences:  A073459 A073460 A073461 * A073463 A073464 A073465 KEYWORD nonn AUTHOR Labos Elemer, Aug 02 2002 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 May 8 19:28 EDT 2021. Contains 343666 sequences. (Running on oeis4.)