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A274910
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Largest prime factor of 11^n - 1.
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5
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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
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OFFSET
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1,1
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LINKS
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J. Brillhart et al., Factorizations of b^n +- 1, Contemporary Mathematics, Vol. 22, Amer. Math. Soc., Providence, RI, 3rd edition, 2002.
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FORMULA
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EXAMPLE
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11^4 - 1 = 14640 = 2^4*3*5*61, so a(4) = 61.
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MATHEMATICA
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Table[FactorInteger[11^n - 1][[-1, 1]], {n, 40}]
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PROG
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(Magma) [Maximum(PrimeDivisors(11^n-1)): n in [1..40]];
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CROSSREFS
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Cf. similar sequences listed in A274906.
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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a(307)-a(316) in b-file from Max Alekseyev, Apr 25 2022, Oct 26 2023
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STATUS
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approved
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