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A159585 Nearest k to j such that k*(2^j-1)+1 is prime where j=A000043(n) and 2^j-1 = Mersenne-prime(n) = A000668(n). If there are two k values equidistant from j, each of which produces a prime, the larger of the two gets added to the sequence. 1
2, 4, 10, 4, 46, 22, 16, 46, 66, 136, 166, 124, 636, 550, 1474, 3066, 1656, 1816, 3708, 9436, 1746, 3696, 11262, 40138, 25900, 20808, 60340, 58818 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..28.

EXAMPLE

n=6, j=A000043(6)=17, A000668(6)=131071, then k=12 or k=22 are the nearest values to j which produce primes so we take the larger of the two k values for a(6)=22.

CROSSREFS

Cf. A000043, A000668, A098556, A101416.

Sequence in context: A302349 A135445 A098556 * A130334 A320537 A331708

Adjacent sequences:  A159582 A159583 A159584 * A159586 A159587 A159588

KEYWORD

hard,nonn

AUTHOR

Ray Chandler, Apr 16 2009

STATUS

approved

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Last modified October 23 12:42 EDT 2021. Contains 348214 sequences. (Running on oeis4.)