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Primes of the form 2^r * 11^s - 1.
4

%I #9 Feb 23 2020 21:20:18

%S 3,7,31,43,127,241,967,5323,8191,117127,131071,524287,7496191,

%T 10307263,77948683,253755391,428717761,738197503,1714871047,

%U 2147483647,16240345087,27437936767,42218553343,1965081755647,2414538435583,7024111812607,7860327022591,16630113370111

%N Primes of the form 2^r * 11^s - 1.

%H Jinyuan Wang, <a href="/A077315/b077315.txt">Table of n, a(n) for n = 1..910</a>

%o (PARI) lista(nn) = {my(q=1/2, p, w=List([])); for(r=0, logint(nn, 2), q=2*q; p=q/11; for(s=0, logint(nn\q, 11), p=11*p; if(ispseudoprime(p-1), listput(w, p-1)))); Set(w); } \\ _Jinyuan Wang_, Feb 23 2020

%Y Cf. A023509, A077313, A077314, A173062.

%K nonn

%O 1,1

%A _Amarnath Murthy_, Nov 04 2002

%E More terms from _Ray Chandler_, Aug 02 2003

%E a(26)-a(28) from _Jinyuan Wang_, Feb 23 2020