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URL: https://oeis.org/A216619

⇱ A216619 - OEIS

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A216619

Numbers k such that 10^k + k^10 - 1 is prime.

1

2, 8, 1592, 2380

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

Next term > 10^4.

a(5) > 10^5. - Robert Price, Oct 08 2015

LINKS

Table of n, a(n) for n=1..4.

MATHEMATICA

Select[Range[0, 5000], PrimeQ[10^# + #^10 - 1] &]

PROG

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

CROSSREFS

Cf. A100357, A215434-A215446, A216375.

Sequence in context: A014116 A027668 A121015 * A306241 A073630 A027733

Adjacent sequences: A216616 A216617 A216618 * A216620 A216621 A216622

KEYWORD

nonn,hard,more

AUTHOR

Vincenzo Librandi, Sep 11 2012

STATUS

approved