login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A124415 Numbers k such that 2*k+1, 4*k+1, 8*k+1, 16*k+1, 32*k+1, 64*k+1 and 128*k+1 are primes. 2
8325, 82950, 884220, 1120470, 3441690, 5627895, 5765505, 7664745, 7757430, 8555040, 10739505, 11891625, 15514860, 15623475, 18268455, 22631970, 24833775, 27373410, 29342895, 31286970, 31577205, 50077455, 51541035, 58646520 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..1000

MATHEMATICA

Select[15*Range[4000000], And @@ PrimeQ /@ ({2, 4, 8, 16, 32, 64, 128}*# + 1) &] (* Ray Chandler, Nov 21 2006 *)

CROSSREFS

Cf. A005097, A123998, A124041, A124412-A124417.

Sequence in context: A170778 A062852 A124414 * A233954 A224465 A031947

Adjacent sequences:  A124412 A124413 A124414 * A124416 A124417 A124418

KEYWORD

nonn,changed

AUTHOR

Artur Jasinski, Nov 02 2006

EXTENSIONS

Corrected and extended by Ray Chandler, Nov 21 2006

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 April 2 23:47 EDT 2020. Contains 333194 sequences. (Running on oeis4.)