OFFSET
1,1
COMMENTS
If p-1 is squarefree, the terms are overpseudoprimes (see A141232). - Vladimir Shevelev, Jul 15 2008
LINKS
G. C. Greubel, Table of n, a(n) for n = 1..440
MATHEMATICA
a = {}; Do[c = (2^Prime[x] + 1)/3; If[PrimeQ[c] == False, AppendTo[a, c]], {x, 2, 30}]; a
Select[(2^Prime[Range[2, 30]]+1)/3, CompositeQ] (* Harvey P. Dale, Feb 04 2015 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Artur Jasinski, Feb 09 2007
STATUS
approved