A128404 Numbers k such that k^2 divides 24^k-1.

1, 23, 1081, 2870377, 7009273, 15954479, 134907719, 329435831, 537539141, 15001987199, 874750261127, 1991103024721, 4272172921319, 4862143429729, 7933540182019, 12816504745411, 41113262272969, 67084347257659

Offset

1,2

Comments

23 divides all terms except the first.

Links

Table of n, a(n) for n=1..18.

Mathematica

a={}; Do[r=(24^n-1)/n^2; If[r==IntegerPart[r], AppendTo[a, n]], {n, 1, 10^3}]; a (* Vladimir Joseph Stephan Orlovsky, Aug 07 2008 *)

Crossrefs

Cf. A127103, A127104, A127105, A127106, A127107, A127102, A127101, A127100, A127092, A128405, A128393, A128394, A128395, A128396, A128397, A128398, A128399, A128400, A128401, A128402, A128403.

Sequence in context: A174748 A042015 A042012 * A126741 A273477 A202656

Adjacent sequences: A128401 A128402 A128403 * A128405 A128406 A128407

Keyword

nonn,less

Author

Alexander Adamchuk, Mar 01 2007

Extensions

a(5)-a(6) from Farideh Firoozbakht, Mar 05 2007

a(7)-a(10) from Ryan Propper, Feb 23 2008

Terms a(11) onward from Max Alekseyev, May 06 2010

Status

approved