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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A020159 Pseudoprimes to base 31. 2
6, 10, 15, 30, 49, 65, 66, 133, 185, 451, 481, 561, 637, 931, 946, 1105, 1221, 1729, 1813, 2317, 2405, 2465, 2553, 3310, 4753, 4921, 6241, 6289, 6601, 7107, 7421, 7449, 8177, 8911, 9073, 9131, 10470, 10585, 10963, 11041, 12403, 14191, 16219, 17767, 18721 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Composite numbers n such that 31^(n-1) == 1 (mod n).

LINKS

R. J. Mathar and T. D. Noe, Table of n, a(n) for n = 1..1000 (R. J. Mathar 837 terms)

Index entries for sequences related to pseudoprimes

MATHEMATICA

base = 31; t = {}; n = 1; While[Length[t] < 100, n++; If[! PrimeQ[n] && PowerMod[base, n-1, n] == 1, AppendTo[t, n]]]; t (* T. D. Noe, Feb 21 2012 *)

CROSSREFS

Cf. A001567 (pseudoprimes to base 2).

Sequence in context: A315288 A238047 A272398 * A048017 A048078 A229276

Adjacent sequences:  A020156 A020157 A020158 * A020160 A020161 A020162

KEYWORD

nonn

AUTHOR

David W. Wilson

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 20 19:36 EDT 2019. Contains 324234 sequences. (Running on oeis4.)