1,1

a(5) > 10^5. - Robert Price, May 11 2015

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

Select[Prime[Range[PrimePi[1000]]], PrimeQ[87^# - 86^#] &] (* T. D. Noe, Aug 15 2012 *)

(PARI) is(n)=ispseudoprime(87^n-86^n) \\ Charles R Greathouse IV, Jun 06 2017

Sequence in context: A266512 A041501 A163488 * A173355 A118222 A191594

Adjacent sequences: A215533 A215534 A215535 * A215537 A215538 A215539

nonn,hard

Jean-Louis Charton, Aug 15 2012

a(4) from Robert Price (computer run by Adam Marciniec), May 11 2015

approved