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A046809 Recursive sequence of indices of Proth primes a*2^b - 1. 0
1, 2, 4, 5, 8, 10, 11, 26, 286, 365, 602, 630, 713, 808, 1327, 3561, 3566, 5286, 5477, 10600, 13485, 15441, 17339, 76856 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Searched up to 76856*2^100000 - 1 (9607*2^100003 - 1 is the format in the Yves Gallot's Proth Program)

LINKS

Table of n, a(n) for n=1..24.

Y. Gallot, Proth.exe: Windows Program for Finding Large Primes

FORMULA

a(n) = least integer greater than a(n-1) such that a(n-1)*2^a(n) - 1 is prime

CROSSREFS

Sequence in context: A067938 A306073 A018457 * A112777 A188972 A047612

Adjacent sequences:  A046806 A046807 A046808 * A046810 A046811 A046812

KEYWORD

hard,nonn

AUTHOR

Chad Davis (cad16(AT)po.cwru.edu)

STATUS

approved

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Last modified September 16 11:47 EDT 2021. Contains 347472 sequences. (Running on oeis4.)