A062657 Numbers k such that 91^k - 90^k is prime.

2, 3, 101, 1117, 3109, 44959, 55259

Offset

1,1

Comments

Terms greater than 1000 are often only strong pseudoprimes.

a(8) > 10^5. - Robert Price, Jul 21 2015

Links

Table of n, a(n) for n=1..7.

Mathematica

Select[Range[0, 100000], PrimeQ[91^# - 90^#] &] (* Robert Price, Jul 21 2015 *)

Prog

(PARI) is(n)=ispseudoprime(91^n-90^n) \\ Charles R Greathouse IV, Jun 13 2017

Crossrefs

Cf. A000043, A057468, A059801, A059802, A062572-A062666.

Sequence in context: A249409 A256114 A345336 * A041589 A371122 A371229

Adjacent sequences: A062654 A062655 A062656 * A062658 A062659 A062660

Keyword

nonn,hard

Author

Mike Oakes, May 18 2001, May 19 2001

Extensions

a(6)-a(7) from Robert Price, Jul 21 2015

Status

approved