

A268352


Second basen Wieferich prime, i.e., second smallest prime p such that n^(p1) == 1 (mod p^2).


1




OFFSET

2,1


COMMENTS

Column 2 of table T(n, k) of kth basen 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).


LINKS

Table of n, a(n) for n=2..10.
R. Fischer, Thema: Fermatquotient B^(P1) == 1 (mod P^2)


EXAMPLE

a(3) = 1006003, because 1006003 is the second smallest prime p satisfying 3^(p1) == 1 (mod p^2) (see A014127).


PROG

(PARI) a(n) = my(i=0); forprime(p=1, , if(Mod(n, p^2)^(p1)==1, if(i > 0, return(p), i++)))


CROSSREFS

Cf. A039951, A178871.
Sequence in context: A043448 A281002 A273472 * A178871 A205071 A263302
Adjacent sequences: A268349 A268350 A268351 * A268353 A268354 A268355


KEYWORD

nonn,hard,more


AUTHOR

Felix FrÃ¶hlich, Feb 02 2016


STATUS

approved



