login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A268479 For p = prime(n), number of primes (including p) in the trajectory of p under the procedure in A244550, also allowing the Wieferich prime 2, that are not terms of a repeating cycle. 3
0, 0, 1, 2, 0, 1, 1, 1, 2, 1, 3, 1, 1, 2 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

COMMENTS

a(15) is unknown, since there is no known Wieferich prime to base 47 (cf. Fischer link).

LINKS

Table of n, a(n) for n=1..14.

R. Fischer, Thema: Fermatquotient B^(P-1) == 1 (mod P^2)

EXAMPLE

The trajectory of 31 starts 31, 7, 5, 2, 1093, 2, 1093, 2, 1093,  ...., entering a repeating cycle consisting of the terms 2 and 1093. There are three terms before the cycle, so a(11) = 3.

CROSSREFS

Cf. A244550, A252801, A252802, A252812.

Sequence in context: A287356 A029402 A330443 * A035196 A287475 A158020

Adjacent sequences:  A268476 A268477 A268478 * A268480 A268481 A268482

KEYWORD

nonn,hard,more

AUTHOR

Felix Fröhlich, Feb 05 2016

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified May 28 07:30 EDT 2022. Contains 354112 sequences. (Running on oeis4.)