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A268352
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Second base-n Wieferich prime, i.e., second smallest prime p such that n^(p-1) == 1 (mod p^2).
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1
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OFFSET
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2,1
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COMMENTS
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Column 2 of table T(n, k) of k-th base-n Wieferich prime for n > 1 (that table is not yet in the OEIS as a sequence).
a(11) is unknown, but must be larger than 1.202*10^13 if it exists (cf. Fischer).
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LINKS
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EXAMPLE
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a(3) = 1006003, because 1006003 is the second smallest prime p satisfying 3^(p-1) == 1 (mod p^2) (see A014127).
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PROG
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(PARI) a(n) = my(i=0); forprime(p=1, , if(Mod(n, p^2)^(p-1)==1, if(i > 0, return(p), i++)))
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CROSSREFS
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KEYWORD
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nonn,hard,more
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AUTHOR
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STATUS
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approved
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