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A102629 a(n)= least k such that (10^k)*Mersenne-prime(n) + 1 is prime. 0
1, 1, 1, 4, 2, 3, 10, 6, 28, 12, 45, 23, 36, 18, 114, 72, 652, 47, 39, 61, 3713, 208 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

COMMENTS

Primes certified using PFGW from Primeform group

LINKS

Table of n, a(n) for n=1..22.

EXAMPLE

(10^1)*(2^5-1)+1=10*31+1=311 prime, 2^5-1=Mersenne-prime(3) so a(3)=1

CROSSREFS

Sequence in context: A278101 A120240 A179394 * A082361 A082363 A026177

Adjacent sequences:  A102626 A102627 A102628 * A102630 A102631 A102632

KEYWORD

nonn

AUTHOR

Pierre CAMI, Feb 01 2005

STATUS

approved

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Last modified November 20 20:46 EST 2019. Contains 329347 sequences. (Running on oeis4.)