A215445 - OEIS

A215445

Numbers k such that 7^k + k^7 - 1 is prime.

1, 11, 65, 133, 679, 1571, 27517, 51631

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

OFFSET

1,2

COMMENTS

a(9) > 10^5. - Robert Price, Feb 23 2014

LINKS

MATHEMATICA

Select[Range[0, 5000], PrimeQ[7^# + #^7 - 1] &]

PROG

(PARI) is(n)=ispseudoprime(7^n+n^7-1) \\ Charles R Greathouse IV, Jun 06 2017

CROSSREFS

KEYWORD

nonn,hard,more

AUTHOR

EXTENSIONS

a(7)-a(8) from Robert Price, Feb 23 2014

STATUS

approved