A128396 Numbers k such that k^2 divides 16^k-1.

1, 3, 5, 15, 21, 39, 55, 105, 155, 165, 195, 205, 273, 465, 609, 615, 903, 915, 1155, 1265, 1365, 1705, 2067, 2145, 2255, 2265, 2373, 2667, 3045, 3081, 3255, 3795, 4305, 4515, 4895, 4965, 5115, 6045, 6123, 6355, 6405, 6765, 7077, 7455, 7917, 7995, 10065

Offset

1,2

Links

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Mathematica

Select[Range[11000], Divisible[16^#-1, #^2]&] (* Harvey P. Dale, Dec 14 2010 *)
Join[{1}, Select[Range[11000], PowerMod[16, #, #^2]==1&]] (* Harvey P. Dale, Mar 16 2022 *)

Crossrefs

Cf. A127103, A127104, A127105, A127106, A127107, A127102, A127101, A127100, A127092, A128405, A128393, A128394, A128396, A128397, A128398, A128399, A128400, A128401, A128402, A128403, A128404.

Sequence in context: A201433 A101129 A177916 * A155173 A202505 A210111

Adjacent sequences: A128393 A128394 A128395 * A128397 A128398 A128399

Keyword

nonn,less

Author

Alexander Adamchuk, Mar 01 2007

Status

approved