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A137907 Least k such that k*(2^p-1)*(k*(2^p-1)-1)+1 is prime, where 2^p-1 runs through the Mersenne primes. 3
1, 1, 9, 6, 9, 24, 4, 7, 28, 70, 73, 121, 511, 106, 343, 2169, 1423, 2146, 5736, 4444, 2484, 2310, 2679, 25623, 2481, 39213 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Table of n, a(n) for n=1..26.

EXAMPLE

1*(2^2-1)*(1*(2^2-1)-1)+1=7 prime, 2^2-1 first Mersenne prime, a(1)=1;

1*(2^3-1)*(1*(2^3-1)-1)+1=43 prime, 2^3-1 second Mersenne prime, a(2)=1.

CROSSREFS

Cf. A137906, A137908, A137909.

Sequence in context: A019790 A033186 A146486 * A070164 A063602 A180572

Adjacent sequences:  A137904 A137905 A137906 * A137908 A137909 A137910

KEYWORD

nonn,hard,more

AUTHOR

Pierre CAMI, Feb 22 2008

EXTENSIONS

Corrected by Pierre CAMI, Jun 16 2012

STATUS

approved

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Last modified July 26 10:48 EDT 2021. Contains 346294 sequences. (Running on oeis4.)