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%I #12 Jan 24 2020 07:00:31
%S 4,5,10,20,40,80,491531,983062,1966124,2457655,3932248,4915310,
%T 6389903,9339089,9830620,12288275,12779806,18678178,19169709,19661240,
%U 24576550,25559612,28017267,31949515,37356356,38339418,39322480,46695445,49153100,51119224,56034534
%N Numbers n such that 7^A000010(n) == 1 (mod n^2).
%H Giovanni Resta, <a href="/A242960/b242960.txt">Table of n, a(n) for n = 1..425</a>
%o (PARI) for(n=2, 10^9, if(Mod(7, n^2)^(eulerphi(n))==1, print1(n, ", ")))
%Y Cf. A077816, A242959, A000010. All primes in this sequence are in A123693.
%K nonn
%O 1,1
%A _Felix Fröhlich_, May 27 2014
%E Terms a(23) and beyond from _Giovanni Resta_, Jan 24 2020