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A128472 a(n) = smallest prime of the form (2n-1)^k - 2 for k>(2n-1), or 0 if no such number exists. 13
0, 79, 6103515623, 5764799, 31381059607 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

a(6) = 11^22420 - 2 was found by Rick L. Shepherd 09/29/2007. It has 23349 decimal digits and it is too large to include.

a(7)-a(12) = {771936328432730777189183517369830159827426282764863750131729657829597399846468418688727, 98526125335693359373, 339448671314611904643504117119, 37589973457545958193355599, 1136272165922724266740722458520499, 480250763996501976790165756943039}.

LINKS

Table of n, a(n) for n=1..5.

Henri Lifchitz & Renaud Lifchitz : PRP Records. Probable Primes Top 10000.

CROSSREFS

Cf. A084714 = smallest prime of the form (2n-1)^k - 2, or 0 if no such number exists.

Cf. A133856 = least number k>(2n-1) such that (2n-1)^k - 2 is prime, or 0 if no such number exists.

Cf. A014224, A109080, A090669, A128455, A128457, A128458, A128459, A128460, A128461. Cf. A133858, A133982.

Sequence in context: A265589 A116327 A060711 * A243432 A093404 A236236

Adjacent sequences:  A128469 A128470 A128471 * A128473 A128474 A128475

KEYWORD

nonn

AUTHOR

Alexander Adamchuk, Mar 14 2007, Oct 01 2007

EXTENSIONS

Edited by Max Alekseyev, Sep 18 2009

STATUS

approved

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Last modified March 23 22:30 EDT 2017. Contains 283985 sequences.