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A249570
Conjectured values of least number k such that k^k + n^n is prime, or 0 if no such k exists.
1
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.
PROG
(PARI) a(n)=k=1; while(!ispseudoprime(k^k+n^n), k++); k
CROSSREFS
Sequence in context: A202697 A369117 A268436 * A051652 A077019 A139037
KEYWORD
nonn,hard,more
AUTHOR
Derek Orr, Nov 01 2014
STATUS
approved