This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A063693 Numbers k such that phi(k + d(k)) = phi(k) + d(k), where phi() = A000010(), d() = A000005(). 1
 3, 5, 11, 17, 24, 29, 41, 42, 56, 59, 71, 98, 101, 102, 107, 137, 149, 179, 191, 197, 227, 230, 239, 248, 264, 269, 281, 294, 311, 347, 419, 431, 461, 468, 521, 569, 599, 617, 638, 641, 659, 809, 821, 827, 857, 881, 1014, 1016, 1019, 1031, 1049, 1061, 1078 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Harry J. Smith, Table of n, a(n) for n = 1..1000 EXAMPLE Primes and composites among solutions: k = 59, d(58) = 2, phi(59) = 58, phi(59+2) = phi(61) = 60 = phi(59) + d(59); k = 56, d(56) = 8, phi(56) = 24, phi(56+8) = phi(64) = 32 = phi(56) + d(56). PROG (PARI) { n=0; for (x=1, 10^9, if (eulerphi(x + numdiv(x)) == (eulerphi(x) + numdiv(x)), write("b063693.txt", n++, " ", x); if (n==1000, break)) ) } \\ Harry J. Smith, Aug 27 2009 CROSSREFS Cf. A000005, A000010. Sequence in context: A158318 A099596 A200748 * A258713 A267517 A309427 Adjacent sequences:  A063690 A063691 A063692 * A063694 A063695 A063696 KEYWORD nonn AUTHOR Labos Elemer, Aug 23 2001 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 23 16:46 EDT 2019. Contains 328373 sequences. (Running on oeis4.)