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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A177884 Pseudoprimes to base 2 of the form 4k+3. 3
1387, 2047, 4371, 8911, 13747, 14491, 19951, 42799, 60787, 90751, 123251, 150851, 256999, 258511, 271951, 272251, 275887, 294271, 387731, 396271, 422659, 435671, 443719, 452051, 476971, 514447, 672487, 680627, 741751, 769567, 877099, 916327, 1024651, 1052503, 1092547, 1152271, 1277179, 1302451, 1325843, 1397419, 1419607, 1433407, 1441091, 1459927 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

In at least the first 1801533 values (that is, for 2-pseudoprimes <10^15) of A001567, the entries of the form 4k+3 are less numerous than those of the form 4k+1. Is this always the case?

LINKS

Charles R Greathouse IV, Table of n, a(n) for n = 1..10000

FORMULA

A001567 INTERSECT A004767.

PROG

(PARI) forstep(n=3, 10^7, 4, if(isprime(n), next()); if(Mod(2, n)^(n-1)==1, print1(n, ", ")))

CROSSREFS

Cf. A001567, A178723.

Sequence in context: A063172 A317972 A216667 * A182123 A200971 A259722

Adjacent sequences:  A177881 A177882 A177883 * A177885 A177886 A177887

KEYWORD

nonn

AUTHOR

Juri-Stepan Gerasimov, Dec 14 2010

EXTENSIONS

Terms corrected by R. J. Mathar, Dec 17 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 February 16 12:48 EST 2019. Contains 320163 sequences. (Running on oeis4.)