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A276040 Least k such that n^n divides phi(k^k) (k > 0). 1

%I

%S 1,4,6,8,10,12,14,12,18,20,22,24,26,28,30,24,34,36,38,40,42,44,46,36,

%T 50,52,45,56,58,60,62,48,66,68,70,72,74,76,78,60,82,84,86,88,90,92,94,

%U 72,98,100,102,104,106,90,110,84,114,116,118,120

%N Least k such that n^n divides phi(k^k) (k > 0).

%C Indices of odd terms in this sequence are 1, 27, 81, 135, 189, 297, 343, 351, 405, 459, 513, 621, 625, 675, 783, ...

%e a(3) = 6 because 3^3 divides phi(6^6) = 15552.

%t Table[k = 1; While[! Divisible[EulerPhi[k^k], n^n], k++]; k, {n, 60}] (* _Michael De Vlieger_, Aug 21 2016 *)

%o (PARI) a(n) = {my(k = 1); while(eulerphi(k^k) % n^n, k++); k; }

%Y Cf. A064447.

%K nonn

%O 1,2

%A _Altug Alkan_, Aug 17 2016

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Last modified May 24 06:53 EDT 2019. Contains 323529 sequences. (Running on oeis4.)