A062588 Numbers k such that 22^k - 21^k is prime.

2, 127, 877

Offset: 1

Author

Mike Oakes, May 18 2001, May 19 2001

Keywords

• nonn
• hard
• bref
• more

Comments

All terms are prime.

No other terms less than 10^5. - Robert Price, May 28 2012

Crossrefs

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

Programs

PARI

is(n)=ispseudoprime(22^n-21^n) \\ Charles R Greathouse IV, Jun 12 2017