A068410 Numbers n such that (n+1) is composite and (n+1) divides 3^n-2^n.

64, 132, 528, 792, 1104, 1648, 1728, 2058, 2320, 2464, 2700, 2820, 4186, 5184, 6304, 6540, 6600, 6696, 6816, 7470, 7612, 8112, 8910, 10584, 10962, 11520, 13212, 13332, 13426, 14700, 14980, 15840, 18720, 19170, 19200, 19908, 21348, 21666, 22176

Offset

1,1

Comments

From little Fermat theorem, if (n+1) is prime (n+1) divides 3^n-2^n

Links

Harvey P. Dale, Table of n, a(n) for n = 1..200

Mathematica

Select[Range[25000], CompositeQ[#+1]&&Mod[3^#-2^#, #+1]==0&] (* Harvey P. Dale, Jul 15 2023 *)

Crossrefs

Sequence in context: A252088 A211254 A252081 * A250654 A223063 A216330

Adjacent sequences: A068407 A068408 A068409 * A068411 A068412 A068413

Keyword

easy,nonn

Author

Benoit Cloitre, Mar 08 2002

Status

approved