%I #25 Oct 20 2020 08:10:17
%S 3,7,3,17,3,15,2,19,3,5,3,43,2,7,3,19,2,5,2,17,3,7,3,167,2,7,3,11,3,3,
%T 2,19,3,2,3,67,2,2,3,17,3,17,2,7,2,5,2,211,2,7,3,7,3,11,3,13,2,3,2,
%U 139,2,2,3,31,3,9,2,5,3,5,2,109,2,5,3,2,2,3,2,85,3,3,3,61
%N Least k > 1 such that k*n is not a totient number.
%C First occurrence of odd k or zero if impossible: 0, 1, 10, 2, 66, 28, 56, 6, 4, 8, 5244, 460, 272, 0, 232, 64, 7788, 4180, 300, 348, 328, 12, etc. - _Robert G. Wilson v_, Feb 09 2017
%H Altug Alkan, <a href="/A282160/b282160.txt">Table of n, a(n) for n = 1..10000</a>
%F a(A079695(n)) = 2. - _Michel Marcus_, Feb 08 2017
%e a(14) = 7 because 7 * 14 = 98 is not a totient number and 7 is the least number that is greater than 1 with this property.
%t TotientQ[m_] := Select[ Range[m +1, 2m*Product[(1 - 1/(k*Log[k]))^(-1), {k, 2, DivisorSigma[0, m]}]], EulerPhi[#] == m &, 1] != {}; (* after Jean-François Alcover, May 23 2011 in A002202 *) f[n_] := Block[{k = 2}, While[ TotientQ[k*n], k++]; k]; Array[f, 84] (* _Robert G. Wilson v_, Feb 09 2017 *)
%o (PARI) a(n) = my(k = 2); while (istotient(k*n), k++); k;
%Y Cf. A000010, A002202, A007617, A067005, A071615, A079695.
%K nonn
%O 1,1
%A _Altug Alkan_, Feb 07 2017