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A134304 Least k such that k*2^n*(k*2^n-1)-1 and k*2^n*(k*2^n-1)+1 are twin primes. 2
2, 1, 2, 1, 11, 21, 57, 211, 141, 156, 78, 39, 140, 70, 35, 214, 107, 90, 45, 309, 330, 165, 120, 60, 30, 15, 435, 651, 420, 210, 105, 429, 1143, 576, 288, 144, 72, 36, 18, 9, 116, 58, 29, 2286, 1143, 1638, 819, 1071, 983, 1983 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..50.

PROG

(PARI) a(n) = {my(k=1); while (!(isprime(p=k*2^n*(k*2^n-1)-1) && isprime(p+2)), k++); k; } \\ Michel Marcus, Sep 17 2019

CROSSREFS

Cf. A134303, A134305.

Sequence in context: A097749 A126906 A179508 * A211096 A134569 A295853

Adjacent sequences:  A134301 A134302 A134303 * A134305 A134306 A134307

KEYWORD

nonn

AUTHOR

Pierre CAMI, Oct 19 2007

STATUS

approved

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Last modified June 16 14:16 EDT 2021. Contains 345057 sequences. (Running on oeis4.)