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!)
A109342 Least k such that (k*M(n))^2+k*M(n)-1 is the first of a pair of twin primes, where M(n) = Mersenne primes. 0
1, 3, 5, 8, 89, 275, 278, 404, 96, 1538, 1253, 15858, 189168, 119552, 636315, 1047122, 3571449 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..17.

EXAMPLE

(3*M(2))^2+3*M(2)-1 = (3*7)^2+3*7-1 = 461, 461 and 463 twin primes so for n=2 k=3

CROSSREFS

Cf. A000043.

Sequence in context: A195548 A174529 A174442 * A121371 A067094 A272235

Adjacent sequences:  A109339 A109340 A109341 * A109343 A109344 A109345

KEYWORD

hard,nonn

AUTHOR

Pierre CAMI, Aug 21 2005; corrected Apr 06 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 September 25 15:16 EDT 2021. Contains 347657 sequences. (Running on oeis4.)