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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A219341 Least prime k such that k*2^n + 1 divides 2^k - 1, or 0 if no such prime exists. 0
2, 3, 0, 11, 397, 839, 1459, 2081, 7297, 53849, 3499, 70589, 792277, 20399, 11173873, 929057, 232591, 6782759, 5834299, 26812151, 40269673, 88529891, 368454343, 616767917, 1167319801, 709939943 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

If a(n) > 0, then a(n)*2^n + 1 is in A122094.

LINKS

Table of n, a(n) for n=0..25.

G. L. Honaker, Jr. and Chris Caldwell, Prime Curios! 232591

Eric Weisstein's World of Mathematics, Mersenne Number

MATHEMATICA

lst = {}; Do[k = 2; If[n == 2, AppendTo[lst, 0], While[True, If[PrimeQ[k], f = k*2^n + 1; If[PrimeQ[f] && PowerMod[2, k, f] == 1, AppendTo[lst, k]; Break[]]]; k++]], {n, 0, 13}]; lst

CROSSREFS

Cf. A001348, A002144.

Sequence in context: A012404 A002099 A265514 * A059740 A005160 A085042

Adjacent sequences:  A219338 A219339 A219340 * A219342 A219343 A219344

KEYWORD

more,nonn

AUTHOR

Arkadiusz Wesolowski, Nov 18 2012

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 March 20 07:42 EDT 2019. Contains 321345 sequences. (Running on oeis4.)