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A274910 Largest prime factor of 11^n - 1. 5
5, 5, 19, 61, 3221, 37, 45319, 7321, 1772893, 13421, 1806113, 1117, 3158528101, 1623931, 195019441, 6304673, 50544702849929377, 1772893, 6115909044841454629, 212601841, 45319, 1806113, 3740221981231, 20113, 1856458657451, 3158528101, 5559917315850179173 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
J. Brillhart et al., Factorizations of b^n +- 1, Contemporary Mathematics, Vol. 22, Amer. Math. Soc., Providence, RI, 3rd edition, 2002.
FORMULA
a(n) = A006530(A024127(n)).
EXAMPLE
11^4 - 1 = 14640 = 2^4*3*5*61, so a(4) = 61.
MATHEMATICA
Table[FactorInteger[11^n - 1][[-1, 1]], {n, 40}]
PROG
(Magma) [Maximum(PrimeDivisors(11^n-1)): n in [1..40]];
CROSSREFS
Cf. similar sequences listed in A274906.
Sequence in context: A246983 A305514 A039914 * A370547 A201803 A151789
KEYWORD
nonn
AUTHOR
Vincenzo Librandi, Jul 11 2016
EXTENSIONS
Terms to a(70) in b-file from Vincenzo Librandi, Jul 13 2016
a(71)-a(306) in b-file from Amiram Eldar, Feb 08 2020
a(307)-a(316) in b-file from Max Alekseyev, Apr 25 2022, Oct 26 2023
STATUS
approved

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Last modified March 4 22:06 EST 2024. Contains 370532 sequences. (Running on oeis4.)