A177819 Numbers k such that k^3 divides 19^(k^2) + 1.

1, 5, 55, 1265, 11255, 59455, 123805, 395755, 635255, 874115, 1028555, 1456015, 2847515, 3201715, 3841805, 4353305, 6655055, 6987805, 13443155, 16825765, 23656765, 36370015, 41083405, 66919765, 68432705, 100126015, 123012395

Offset: 1

Author

Alexander Adamchuk, May 14 2010

Keywords

• nonn

Comments

5 divides a(n) for n > 1.

Crossrefs

Cf. A127263 (k^3 divides 2^(k^2) + 1).

Cf. A128678, A128679, A128680, A128681, A128682, A128683, A128684, A128685.

Cf. A177813, A177814, A177816, A177817, A177818, A177819, A177820.

Cf. A128677 (least k > p such that (k*p)^3 divides (p-1)^(k*p)^2+1, where p = prime(n) > 2).

Programs

Mathematica

Select[Range[123020000],PowerMod[19,#^2,#^3]==#^3-1&] (* Harvey P. Dale, May 20 2021 *)

Extensions

More terms from Max Alekseyev, May 16 2010