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

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A066152 Numbers k such that EulerPhi(k) = sigma(k+1) - sigma(k). 1
 2, 459, 17835, 34089, 55419, 61183, 180785, 194139, 248501, 385671, 907323, 988455, 1374735, 1407413, 1408253, 1452135, 1749087, 2451727, 3026705, 3263585, 3831487, 6541695, 7633989, 9336785, 12750833, 16543433, 16573963, 21248201 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Harry J. Smith, Table of n, a(n) for n = 1..70 EXAMPLE EulerPhi(459) = 288 = 1008 - 720 = sigma(460) - sigma(459). [corrected by Harry J. Smith, Feb 03 2010] MATHEMATICA Select [Range[1, 10^6], EulerPhi[ # ] == DivisorSigma[1, # + 1] - DivisorSigma[1, # ] & ] PROG (PARI) { n=0; for (m=1, 10^9, if (eulerphi(m) == sigma(m + 1) - sigma(m), write("b066152.txt", n++, " ", m); if (n==70, return)) ) } \\ Harry J. Smith, Feb 03 2010 CROSSREFS Sequence in context: A012730 A012734 A099686 * A112862 A094484 A062620 Adjacent sequences: A066149 A066150 A066151 * A066153 A066154 A066155 KEYWORD nonn AUTHOR Joseph L. Pe, Dec 13 2001 EXTENSIONS More terms from Robert G. Wilson v, Dec 27 2001 a(25)-a(28) from Harry J. Smith, Feb 03 2010 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 June 10 09:03 EDT 2023. Contains 363196 sequences. (Running on oeis4.)