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A007571 a(n) = largest prime factor of n^n + 1.
(Formerly M1343)
11
2, 5, 7, 257, 521, 97, 911, 673, 530713, 27961, 58367, 2227777, 79301, 176597, 142111, 67280421310721, 45957792327018709121, 33388093, 870542161121, 4406613081041681, 22864311556633, 73194743542229, 1522029233, 27250359649 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
REFERENCES
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
LINKS
Tyler Busby, Table of n, a(n) for n = 1..148 (terms 1..123 from Hugo Pfoertner, terms 124..135 from Yurii Ivanov)
FORMULA
a(n) = A006530(A014566(n)). - Michel Marcus, Aug 24 2019
MATHEMATICA
Table[ FactorInteger[ n^n + 1, FactorComplete -> True ] [ [ -1, 1 ] ], {n, 1, 25} ]
PROG
(PARI) for(k=1, 24, my(x=factor(k^k+1), f=x[#x[, 1], 1]); print1(f, ", ")) \\ Hugo Pfoertner, Aug 23 2019
(Magma) [Max(PrimeDivisors(n^n+1)):n in [1..24]]; // Marius A. Burtea, Aug 24 2019
CROSSREFS
Sequence in context: A042673 A214705 A252283 * A350590 A062621 A306748
KEYWORD
nonn,hard
AUTHOR
STATUS
approved

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Last modified March 19 01:22 EDT 2024. Contains 370952 sequences. (Running on oeis4.)