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%I #20 Apr 23 2017 22:36:13
%S 2320690177,17069520863233,42182344790209,65465530560001,
%T 3432376805760001,13322002122777601,20388795375960001,
%U 129009714848870401,580007888606160001,1096591987029196801,3029756968906340401,5806765663003468801,6213994663149504001,6367205158826803201,7802569551798000001,10319507991273499201
%N Numbers n > 2 such that lambda(n)^2 divides n-1, where lambda(n) = A002322(n).
%C Squarefree numbers n > 2 such that (p-1)^2 | n-1 for every prime p|n.
%C For the first five terms, lambda(n)^2 | phi(n). - _Thomas Ordowski_, Apr 11 2017
%o (PARI) isok(n) = (n % lcm(znstar(n)[2])^2) == 1; \\ _Michel Marcus_, Apr 22 2017
%Y Subsequence of A002997 and of A277389.
%Y Cf. A002322.
%K nonn
%O 1,1
%A _Thomas Ordowski_ and _Charles R Greathouse IV_, Oct 28 2016
%E a(7)-a(16) from _Max Alekseyev_, Apr 23 2017
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