This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A171259 Numbers n such that sigma(n) = 14*phi(n) (where sigma=A000203, phi=A000010). 5
 420, 2730, 5940, 12540, 24024, 38610, 48360, 66528, 77490, 81510, 133920, 140448, 141372, 156420, 163590, 282720, 284580, 298452, 348348, 498420, 600780, 681912, 701220, 771420, 792480, 901530, 918918, 1016730, 1052220, 1150968, 1372680, 1439592, 1654620 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Donovan Johnson, Table of n, a(n) for n = 1..1000 Kevin A. Broughan and Daniel Delbourgo, On the Ratio of the Sum of Divisors and Eulerâ€™s Totient Function I, Journal of Integer Sequences, Vol. 16 (2013), Article 13.8.8. Kevin A. Broughan and Qizhi Zhou, On the Ratio of the Sum of Divisors and Euler's Totient Function II, Journal of Integer Sequences, Vol. 17 (2014), Article 14.9.2. PROG (PARI) for(k=1, 2e6, sigma(k) - 14*eulerphi(k) | print1(k", ")); CROSSREFS Cf. A062699, A068391, A068390, A136547, A104900, A136540, A104901, A163667, A171256, A171257, A104902, A171258, A171260, A104903. Sequence in context: A250383 A145678 A160372 * A061125 A269016 A317983 Adjacent sequences:  A171256 A171257 A171258 * A171260 A171261 A171262 KEYWORD nonn AUTHOR Farideh Firoozbakht and M. F. Hasler, Mar 19 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 | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified March 18 17:51 EDT 2019. Contains 321292 sequences. (Running on oeis4.)