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A363371 a(n) is the least prime p for which (p-1)*phi(p^n) is a nontotient, where phi is the Euler totient function (A000010).

%I A363371 #9 May 29 2023 11:55:45
%S A363371 23,11,23,11,23,11,47,11,11,23,47,23,23,23,47,47,103,103,103,103,103,
%T A363371 103,167,103,103,103,103,103,103,103,103,103,103,179,103,103,103,103,
%U A363371 103,103,103,103,127,103,103,103,103,103,103,103,103,103,103,127,127,103,127,127,127
%N A363371 a(n) is the least prime p for which (p-1)*phi(p^n) is a nontotient, where phi is the Euler totient function (A000010).
%C A363371 Thus a(n) is the least prime p for which p-1=phi(p), a totient value, multiplied by phi(p^n), another totient value, gives a nontotient. There are several instances of these numbers in A361058.
%H A363371 Michel Marcus, <a href="/A363371/b363371.txt">Table of n, a(n) for n = 1..160</a>
%o A363371 (PARI) a(n) = my(p=2); while (istotient((p-1)*eulerphi(p^n)), p = nextprime(p+1)); p;
%Y A363371 Cf. A000010, A002202 (totient values) A005277 (nontotients), A361058.
%K A363371 nonn
%O A363371 1,1
%A A363371 _Michel Marcus_, May 29 2023