A179866 - OEIS

%I #11 May 01 2013 21:02:11

%S 2,1531,16651,15514861

%N A057330 with duplicates omitted.

%e 2*2-1=3,2*3-1=5,2*5-1=11;

%e 2,3,5;

%e 1531,3061,6121,12241,24481;

%e 16651,33301,66601,133201,266401,532801,1065601;

%e 15514861,31029721,62059441,124118881,248237761,496475521,992951041,1985902081;

%t q=1; Reap[Do[lst={a=Prime[n]}; While[PrimeQ[a=2a-1], AppendTo[lst,a]]; If[Length[lst]>q, q=Length[lst]; Print[lst]; Sow[lst[[1]]]], {n,10^6}]][[2,1]]

%Y Cf. A057330, A005382

%K nonn,more

%O 1,1

%A _Vladimir Joseph Stephan Orlovsky_, Jan 11 2011

%E Edited by _N. J. A. Sloane_, Jan 11 2011.