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A122166
Numbers n such that 1 + Sum k^k (k=1..n) is prime.
3
1, 52, 124, 431
OFFSET
1,2
COMMENTS
Primes of the form A001923[n] = Sum k^k (k=1..n) are given in A073826[n] and their indices are given in A073825[n] = {2,5,6,10,30,...}.
MATHEMATICA
s=1; Do[s=s+k^k; If[PrimeQ[s], Print[{k, s}]], {k, 1, 500}]
CROSSREFS
Sequence in context: A327147 A346898 A120534 * A205221 A044303 A044684
KEYWORD
nonn
AUTHOR
Alexander Adamchuk, Aug 23 2006
STATUS
approved