%I #9 May 06 2018 12:45:09
%S 178956971,45812984491,733007751851,46912496118443,3002399751580331,
%T 192153584101141163,49191317529892137643,787061080478274202283,
%U 3148244321913096809131,3223802185639011132549803
%N Composite numbers of the form (2^p+1)/3 where p is a prime.
%C If p-1 is squarefree, the terms are overpseudoprimes (see A141232). - _Vladimir Shevelev_, Jul 15 2008
%H G. C. Greubel, <a href="/A127955/b127955.txt">Table of n, a(n) for n = 1..440</a>
%t a = {}; Do[c = (2^Prime[x] + 1)/3; If[PrimeQ[c] == False, AppendTo[a, c]], {x, 2, 30}]; a
%t Select[(2^Prime[Range[2,30]]+1)/3,CompositeQ] (* _Harvey P. Dale_, Feb 04 2015 *)
%Y Cf. A000979, A000978, A124400, A126614, A127956, A127957.
%K nonn
%O 1,1
%A _Artur Jasinski_, Feb 09 2007