login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A070418 Numbers n such that n and phi(n) have the same number of divisors. 4
1, 3, 14, 15, 22, 28, 44, 46, 50, 56, 68, 70, 78, 88, 92, 94, 110, 112, 118, 166, 174, 176, 184, 188, 198, 214, 224, 228, 230, 234, 236, 255, 260, 294, 306, 318, 332, 334, 342, 352, 358, 368, 376, 414, 428, 448, 454, 462, 470, 472, 492, 500, 526, 550, 580, 590 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

G. C. Greubel, Table of n, a(n) for n=1..8407 (for values up to 500000)

MATHEMATICA

Select[Range[600], DivisorSigma[0, #]==DivisorSigma[0, EulerPhi[#]]&] (* Harvey P. Dale, Sep 04 2015 *)

PROG

(PARI) for(n=1, 900, if(numdiv(n)==numdiv(eulerphi(n)), print1(n, ", ")))

CROSSREFS

Sequence in context: A171653 A055435 A242868 * A178363 A294997 A034120

Adjacent sequences:  A070415 A070416 A070417 * A070419 A070420 A070421

KEYWORD

easy,nonn

AUTHOR

Benoit Cloitre, May 12 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.

License Agreements, Terms of Use, Privacy Policy. .

Last modified September 28 20:26 EDT 2021. Contains 347717 sequences. (Running on oeis4.)