%I #9 Jun 06 2021 09:03:26
%S 1,5,55,1265,11255,59455,123805,395755,635255,874115,1028555,1456015,
%T 2847515,3201715,3841805,4353305,6655055,6987805,13443155,16825765,
%U 23656765,36370015,41083405,66919765,68432705,100126015,123012395
%N Numbers k such that k^3 divides 19^(k^2) + 1.
%C 5 divides a(n) for n > 1.
%t Select[Range[123020000],PowerMod[19,#^2,#^3]==#^3-1&] (* _Harvey P. Dale_, May 20 2021 *)
%Y Cf. A127263 (k^3 divides 2^(k^2) + 1).
%Y Cf. A128678, A128679, A128680, A128681, A128682, A128683, A128684, A128685.
%Y Cf. A177813, A177814, A177816, A177817, A177818, A177819, A177820.
%Y Cf. A128677 (least k > p such that (k*p)^3 divides (p-1)^(k*p)^2+1, where p = prime(n) > 2).
%K nonn
%O 1,2
%A _Alexander Adamchuk_, May 14 2010
%E More terms from _Max Alekseyev_, May 16 2010
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