login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A039914 Smallest k>1 such that k(p-1)-1 is divisible by p^2, p=n-th prime. 2
5, 5, 19, 41, 109, 155, 271, 341, 505, 811, 929, 1331, 1639, 1805, 2161, 2755, 3421, 3659, 4421, 4969, 5255, 6161, 6805, 7831, 9311, 10099, 10505, 11341, 11771, 12655, 16001, 17029, 18631, 19181, 22051, 22649, 24491, 26405, 27721, 29755, 31861 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..41.

EXAMPLE

a(1)=5 because 5(2-1)-1=4 is divisible by 2^2.

PROG

(PARI) a(n) = {my(p = prime(n), k = 2); while ((k*(p-1)-1) % p^2, k++); k; } \\ Michel Marcus, Sep 28 2013

CROSSREFS

Cf. A039678.

A306190 is an essentially identical sequence.

Sequence in context: A145937 A246983 A305514 * A274910 A201803 A151789

Adjacent sequences:  A039911 A039912 A039913 * A039915 A039916 A039917

KEYWORD

nonn

AUTHOR

Felice Russo

EXTENSIONS

Added constraint on k to the definition, otherwise a(1)=1 - R. J. Mathar, Oct 10 2010

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 15 18:22 EDT 2019. Contains 327082 sequences. (Running on oeis4.)