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!)
A124141 Numbers k such that there is a number m < k satisfying A000203(k) = A000203(m) = m + k - gcd(m,k). 1
38, 92, 153, 284, 332, 459, 494, 885, 956, 1035, 1358, 1784, 2295, 2528, 2678, 5434, 5607, 6027, 6255, 7564, 7928, 8235, 8648, 9729, 10325, 10413, 12008, 14104, 15813, 16198 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..30.

EXAMPLE

38 is in the sequence because A000203(24) = A000203(38) = 60 = 24 + 38 - gcd(24,38).

PROG

(PARI) isok(k) = {my(sk = sigma(k)); for (m=1, k, if ((sk == sigma(m)) && (sk == m + k - gcd(m, k)), return (1)); ); return (0); } \\ Michel Marcus, Oct 27 2019

CROSSREFS

Cf. A124140.

Subsequence of A069822.

Sequence in context: A235087 A235080 A218331 * A093649 A020167 A186439

Adjacent sequences:  A124138 A124139 A124140 * A124142 A124143 A124144

KEYWORD

nonn,more

AUTHOR

Yasutoshi Kohmoto, Dec 01 2006

EXTENSIONS

Edited by Stefan Steinerberger, Aug 14 2007

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 June 12 14:45 EDT 2021. Contains 344957 sequences. (Running on oeis4.)