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!)
A242960 Numbers n such that 7^A000010(n) == 1 (mod n^2). 10
4, 5, 10, 20, 40, 80, 491531, 983062, 1966124, 2457655, 3932248, 4915310, 6389903, 9339089, 9830620, 12288275, 12779806, 18678178, 19169709, 19661240, 24576550, 25559612, 28017267, 31949515, 37356356, 38339418, 39322480, 46695445, 49153100, 51119224, 56034534 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Giovanni Resta, Table of n, a(n) for n = 1..425

PROG

(PARI) for(n=2, 10^9, if(Mod(7, n^2)^(eulerphi(n))==1, print1(n, ", ")))

CROSSREFS

Cf. A077816, A242959, A000010. All primes in this sequence are in A123693.

Sequence in context: A185875 A049898 A166577 * A288141 A203853 A109675

Adjacent sequences:  A242957 A242958 A242959 * A242961 A242962 A242963

KEYWORD

nonn

AUTHOR

Felix Fröhlich, May 27 2014

EXTENSIONS

Terms a(23) and beyond from Giovanni Resta, Jan 24 2020

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 May 25 16:33 EDT 2020. Contains 334595 sequences. (Running on oeis4.)