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A109137 Numbers n such that n * (10^n - 1) + 1 is prime. 0
2, 14, 42, 144, 200, 302, 7242, 8718 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Larger values certified with ECM. No more up to 6000.

LINKS

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

PROG

(PARI) is(n)=ispseudoprime(n*(10^n-1)+1) \\ Charles R Greathouse IV, Jun 13 2017

CROSSREFS

Cf. A110807.

Sequence in context: A230801 A231081 A152670 * A192375 A267247 A297425

Adjacent sequences:  A109134 A109135 A109136 * A109138 A109139 A109140

KEYWORD

more,nonn

AUTHOR

Jason Earls, Aug 18 2005

EXTENSIONS

2 more terms from Ryan Propper, Sep 20 2006

STATUS

approved

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Last modified June 12 23:22 EDT 2021. Contains 344980 sequences. (Running on oeis4.)