A249570 Conjectured values of least number k such that k^k + n^n is prime, or 0 if no such k exists.

1, 1, 2, 1, 0, 25, 2, 157, 0, 7, 48, 23, 40, 3, 4, 25, 0, 7, 70, 31, 74, 57, 12, 203, 4, 945, 14, 33, 0, 0, 20, 93, 28, 193, 2442, 0, 728, 183, 70, 13, 0, 0, 2, 13, 0, 0, 0, 11, 0, 0, 0, 0, 0, 0, 14, 0, 22, 0, 0, 0, 72, 109, 0, 85, 0, 73, 0, 0, 0, 19, 0, 61, 12, 21, 4, 0, 570, 0, 0, 177, 1532, 0, 0, 55, 64, 75, 602, 151, 0, 133, 0, 0, 32, 33, 3786, 0, 122, 0, 0

Offset

1,3

Comments

The zero entries are only conjectural.

a(5) > 10000 or 0. Other a(n) = 0 entries have been checked up to k = 7500.

If a(i) = j, then a(j) <= i.

Links

Table of n, a(n) for n=1..99.

Prog

(PARI) a(n)=k=1; while(!ispseudoprime(k^k+n^n), k++); k

Crossrefs

Sequence in context: A202697 A369117 A268436 * A051652 A077019 A139037

Adjacent sequences: A249567 A249568 A249569 * A249571 A249572 A249573

Keyword

nonn,hard,more

Author

Derek Orr, Nov 01 2014

Status

approved