A055689 -id:A055689 - cp's OEIS frontend

A055686 Numbers k such that 3^k == -1 (mod k-1).

2, 3, 5, 6, 15, 245, 366, 435, 855, 2295, 3795, 5967, 7875, 10878, 26475, 33915, 117615, 188775, 231435, 284355, 487635, 501039, 589155, 593775, 621675, 755595, 1255815, 1306935, 1642095, 1911195, 2193125, 2434755, 2484675, 2507835

Offset: 1

Robert G. Wilson v, Jun 09 2000

nonn

Amiram Eldar, Table of n, a(n) for n = 1..1000

Cf. A055685, A055687, A055688, A055689, A055690, A055691, A055692, A055693, A055694, A055695.

Do[If[PowerMod[3, n, n-1]==n-2, Print[n]], {n, 2, 10^7}]

A055688 Numbers k such that 5^k == -1 (mod k-1).

Original entry on oeis.org

2, 3, 7, 14, 15, 175, 855, 2695, 78127, 103974, 106695, 121975, 420210, 487375, 1299375, 2174655, 3895095, 4151455, 5842215, 5951130, 6508335, 10637055, 20117895, 24482958, 31999695, 32282054, 32620203, 32872455, 34258455

Offset: 1

Robert G. Wilson v, Jun 09 2000

nonn

Amiram Eldar, Table of n, a(n) for n = 1..200

Cf. A055685, A055686, A055687, A055689, A055690, A055691, A055692, A055693, A055694, A055695.

Do[If[PowerMod[5, n, n-1]==n-2, Print[n]], {n, 2, 10^8}]
Select[Range[2,35*10^6],PowerMod[5,#,#-1]==#-2&] (* Harvey P. Dale, Aug 13 2024 *)

a(22) corrected by Amiram Eldar, Jul 23 2021

A055690 Numbers k such that 7^k == -1 (mod k-1).

Original entry on oeis.org

2, 3, 5, 6, 9, 26, 45, 66, 87, 345, 765, 906, 3926, 8405, 11766, 23805, 35145, 42966, 59685, 95289, 317250, 413325, 416757, 722745, 770066, 890825, 938457, 1325826, 1921986, 3315378, 3675555, 5299250, 6791445, 6899685, 9371826, 10892313

Offset: 1

Robert G. Wilson v, Jun 09 2000

nonn

Amiram Eldar, Table of n, a(n) for n = 1..285

Cf. A055685, A055686, A055687, A055688, A055689, A055691, A055692, A055693, A055694, A055695.

Do[If[PowerMod[7, n, n-1]==n-2, Print[n]], {n, 2, 2*10^7}]

cp's OEIS Frontend

A055686 Numbers k such that 3^k == -1 (mod k-1).

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A055688 Numbers k such that 5^k == -1 (mod k-1).

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Author

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Programs

Mathematica

Extensions

A055690 Numbers k such that 7^k == -1 (mod k-1).

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Author

Keywords

Links

Crossrefs

Programs

Mathematica