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A133378
a(1)=1. For n >= 2, a(n) = the largest prime divisor of (a(n-1)^a(n-1) + 1).
0
OFFSET
1,2
COMMENTS
a(5) depends on the factorization of the 1408-digit composite number (521^521+1)/(2 * 3^2 * 29 * 375121); see factordb.com link. - Michael S. Branicky, Jan 27 2023
MATHEMATICA
NestList[FactorInteger[#^#+1][[-1, 1]]&, 1, 3] (* Harvey P. Dale, Jun 21 2012 *)
CROSSREFS
Cf. A007571.
Sequence in context: A138696 A163798 A081296 * A283561 A037063 A068105
KEYWORD
more,nonn
AUTHOR
Leroy Quet, Oct 28 2007
STATUS
approved