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A137906 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, 1, 1, 1, 4, 1, 27, 14, 34, 6, 132, 97, 1, 500, 1816, 1292, 136, 2445, 15, 1934, 5472, 1584, 2734, 21022, 5870 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,6

LINKS

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

EXAMPLE

1*(2^2-1)*(1*(2^2-1)-1)-1=5 prime, 2^2-1 first Mersenne prime, a(1)=1;

1*(2^3-1)*(1*(2^3-1)-1)-1=41 prime, 2^3-1 second Mersenne prime, a(2)=1.

CROSSREFS

Cf. A137907, A137908, A137909.

Sequence in context: A095891 A095887 A225213 * A139051 A061692 A096206

Adjacent sequences:  A137903 A137904 A137905 * A137907 A137908 A137909

KEYWORD

nonn,hard,more

AUTHOR

Pierre CAMI, Feb 22 2008

STATUS

approved

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