The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A039786 phi(a(n)) is equal to the multiplicative projection of (a(n)-1). 1
 2, 3, 5, 7, 9, 11, 13, 23, 29, 31, 43, 47, 53, 59, 61, 67, 71, 79, 83, 103, 107, 131, 139, 149, 157, 167, 173, 179, 191, 211, 223, 227, 229, 239, 263, 269, 277, 283, 293, 311, 317, 331, 347, 349, 359, 367, 373, 383, 389, 419, 421, 431, 439, 443, 461, 463, 467, 479 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Only primes (except 9) may qualify. LINKS Charles R Greathouse IV, Table of n, a(n) for n = 1..10000 EXAMPLE phi(29)=28, 28=2^2*7^1, 2*2*7*1=28. PROG (PARI) is(n)=my(f=factor(n)); eulerphi(f)==prod(i=1, #f~, f[i, 1]*f[i, 2])-1 \\ Charles R Greathouse IV, Mar 11 2014 CROSSREFS Cf. A000010, A000026. Sequence in context: A189710 A024678 A265384 * A102422 A062427 A127721 Adjacent sequences: A039783 A039784 A039785 * A039787 A039788 A039789 KEYWORD nonn AUTHOR Olivier Gérard EXTENSIONS a(1) inserted by Charles R Greathouse IV, Mar 11 2014 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 September 10 06:17 EDT 2024. Contains 375773 sequences. (Running on oeis4.)