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!)
A092590 a(n) = A065395(A000040(n)); values of commutator of sigma and phi function at prime number arguments. 1
-1, 1, 5, 8, 14, 22, 25, 31, 28, 48, 56, 73, 78, 76, 56, 80, 74, 138, 112, 120, 159, 136, 102, 156, 210, 185, 168, 126, 240, 212, 248, 212, 226, 240, 226, 300, 314, 283, 204, 252, 222, 474, 296, 412, 339, 388, 472, 360, 270, 472, 378, 368, 634, 396, 427, 316, 404, 592, 534, 628, 436, 434, 582, 480, 684, 456, 700, 836 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

The sequence differs from A065394 since it is not monotonic.

LINKS

Table of n, a(n) for n=1..68.

EXAMPLE

a(1) = sigma(phi(2))- phi(sigma(2)) = sigma(1)-phi(3) = 1-2 = -1.

PROG

(MAGMA) [DivisorSigma(1, EulerPhi(p))-EulerPhi(DivisorSigma(1, p)): p in PrimesUpTo(400)]; // Bruno Berselli, Oct 20 2015

CROSSREFS

Cf. A000010, A000040, A000203, A033632, A065393-A065395, A092584-A092589.

Sequence in context: A314524 A314525 A314526 * A065394 A124011 A101835

Adjacent sequences:  A092587 A092588 A092589 * A092591 A092592 A092593

KEYWORD

sign,look

AUTHOR

Labos Elemer, Mar 03 2004

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 April 11 06:40 EDT 2021. Contains 342886 sequences. (Running on oeis4.)