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A231735 Least positive k such that n*k^k - 1 is a prime, or 0 if no such k exists. 3
2, 2, 1, 1, 2, 1, 1128, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

After the missing a(9) the sequence continues: 3, 2, 1, 6, 1, 2, 3, 2, 1, 6, 1, 2, 3, 14, 1.

LINKS

Table of n, a(n) for n=1..8.

EXAMPLE

Least k>0 such that 5*k^k-1 is a prime is k=2, so a(5)=2.

CROSSREFS

Cf. A000040, A193807, A231734.

Sequence in context: A209332 A020945 A231734 * A016429 A131852 A139352

Adjacent sequences:  A231732 A231733 A231734 * A231736 A231737 A231738

KEYWORD

nonn,hard,more

AUTHOR

Alex Ratushnyak, Nov 12 2013

STATUS

approved

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Last modified September 25 16:16 EDT 2017. Contains 292499 sequences.