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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A015921 Positive integers n such that 2^n == 4 (mod n). 16
1, 2, 4, 6, 10, 12, 14, 22, 26, 30, 34, 38, 46, 58, 62, 74, 82, 86, 94, 106, 118, 122, 132, 134, 142, 146, 158, 166, 170, 178, 182, 194, 202, 206, 214, 218, 226, 254, 262, 274, 278, 298, 302, 314, 326, 334, 346, 358, 362, 372, 382, 386, 394, 398, 422, 446 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Odd terms are given by A173572.

For all m, 2^A050259(m)-1 belongs to this sequence.

LINKS

T. D. Noe, Table of n, a(n) for n = 1..1000

OEIS Wiki, 2^n mod n

MATHEMATICA

Select[Range[500], PowerMod[2, #, #] == 4 &] (* Alonso del Arte, Jul 07 2011 *)

CROSSREFS

Contains A050990 as a subsequence.

Cf. A015910, A173572.

Sequence in context: A301646 A024892 A087136 * A232964 A132631 A248614

Adjacent sequences:  A015918 A015919 A015920 * A015922 A015923 A015924

KEYWORD

nonn

AUTHOR

Robert G. Wilson v

EXTENSIONS

Edited and terms 1,2,4 prepended by Max Alekseyev, Jul 29 2011

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 October 17 01:03 EDT 2019. Contains 328103 sequences. (Running on oeis4.)