A062637 Numbers k such that 71^k - 70^k is prime.

47, 139, 227, 2339, 4919, 21319

Offset

1,1

Comments

Terms greater than 1000 are often only strong pseudoprimes.

a(7) > 10^5. - Robert Price, Feb 17 2014

Links

Table of n, a(n) for n=1..6.

Prog

(PARI) is(n)=ispseudoprime(71^n-70^n) \\ Charles R Greathouse IV, Jun 13 2017

Crossrefs

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

Sequence in context: A095311 A005112 A355727 * A212374 A040984 A136070

Adjacent sequences: A062634 A062635 A062636 * A062638 A062639 A062640

Keyword

nonn,hard

Author

Mike Oakes, May 18 2001, May 19 2001

Extensions

a(6) from Robert Price, Feb 17 2014

Status

approved