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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A145042 Primes p (A000043) such that 2^p-1 is prime (A000668) and congruent to 127 mod 6! 7
7, 19, 31, 127, 607, 1279, 2203, 4423, 110503, 216091, 1257787, 20996011, 24036583 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Mersenne numbers (with exception first two) are congruent to 31, 127, 271, 607 mod 6!. This sequences is subset of A000043.

LINKS

Table of n, a(n) for n=1..13.

MATHEMATICA

p = {2, 3, 5, 7, 13, 17, 19, 31, 61, 89, 107, 127, 521, 607, 1279, 2203, 2281, 3217, 4253, 4423, 9689, 9941, 11213, 19937, 21701, 23209, 44497, 86243, 110503, 132049, 216091, 756839, 859433, 1257787, 1398269, 2976221, 3021377, 6972593, 13466917, 20996011, 24036583, 25964951, 30402457, 32582657, 37156667, 43112609}; a = {}; Do[If[Mod[2^p[[n]] - 1, 6! ] == 127, AppendTo[a, p[[n]]]], {n, 1, Length[p]}]; a (*Artur Jasinski*)

CROSSREFS

Cf. A000043, A000668, A124477, A139484, A145038, A112633, A145041, A145042, A145044, A145045, A145046.

Sequence in context: A237366 A216531 A216564 * A153892 A038869 A147503

Adjacent sequences:  A145039 A145040 A145041 * A145043 A145044 A145045

KEYWORD

nonn

AUTHOR

Artur Jasinski, Sep 30 2008

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 | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified August 18 16:13 EDT 2018. Contains 313833 sequences. (Running on oeis4.)