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

 

Logo

Many excellent designs for a new banner were submitted. We will use the best of them in rotation.

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A178723 Pseudoprimes to base 2 of the form 4k+1. 1
341, 561, 645, 1105, 1729, 1905, 2465, 2701, 2821, 3277, 4033, 4369, 4681, 5461, 6601, 7957, 8321, 8481, 10261, 10585, 11305, 12801, 13741, 13981, 15709, 15841, 16705, 18705, 18721, 23001, 23377, 25761, 29341, 30121, 30889, 31417, 31609, 31621, 33153, 34945, 35333, 39865, 41041, 41665, 46657, 49141, 49981, 52633 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..48.

PROG

(PARI) forstep(n=5, 10^7, 4, if(isprime(n), next()); if(Mod(2, n)^(n-1)==1, print1(n, ", ")))

CROSSREFS

Cf. A001567, A177884.

Sequence in context: A025353 A025345 A001567 * A210993 A006970 A007324

Adjacent sequences:  A178720 A178721 A178722 * A178724 A178725 A178726

KEYWORD

nonn

AUTHOR

Joerg Arndt, Dec 30 2010

STATUS

approved

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

Content is available under The OEIS End-User License Agreement .

Last modified April 18 18:49 EDT 2014. Contains 240732 sequences.