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A082747 Least k such that k*Mrs(n)*Mrs(n+1)*Mrs(n+2) +1 is prime with Mrs(i)=i-th Mersenne-prime. 0
2, 4, 6, 4, 60, 280, 60, 210, 306, 154, 538, 1272, 640, 4180, 6384 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..15.

EXAMPLE

2*(2^2-1)*(2^3-1)*(2^5-1) +1 = 1303 prime so a(1)=2

CROSSREFS

Sequence in context: A293473 A257080 A099784 * A127275 A242796 A298527

Adjacent sequences:  A082744 A082745 A082746 * A082748 A082749 A082750

KEYWORD

hard,more,nonn

AUTHOR

Pierre CAMI, Oct 22 2004

STATUS

approved

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Last modified May 26 19:38 EDT 2019. Contains 323597 sequences. (Running on oeis4.)