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%I #29 Dec 12 2020 01:42:15
%S 1,3,21,27,37,43,91,117,141,163,373,421,1581,2035,10701,18931,21307,
%T 51195,64579,156541,302097,334257,368059,383061,410131,494317,541621,
%U 990219,1039965,1526097,1589157,1695499,1954243,2033941
%N Numbers n such that 121*2^n-1 is a prime.
%C 4553899 is also in the sequence. - _Felix Fröhlich_, Jul 04 2014
%H Author?, <a href="https://web.archive.org/web/20110601231527/www.bodang.com/12121/">12121 Search</a> [Archived at Wayback Machine].
%H Ray Ballinger and Wilfrid Keller, <a href="http://www.prothsearch.com/riesel1.html">List of primes k.2^n + 1 for k < 300</a>
%H Wilfrid Keller, <a href="http://www.prothsearch.com/riesel2.html">List of primes k.2^n - 1 for k < 300</a>
%H Kosmaj, <a href="http://www.15k.org/riesellist.html">Riesel list k<300</a>.
%H PrimeGrid, <a href="http://www.primegrid.com/download/27121-4553899.pdf">Announcement of n=4553899</a> - _Felix Fröhlich_, Jul 04 2014
%H <a href="/index/Pri#riesel">Index entries for sequences of n such that k*2^n-1 (or k*2^n+1) is a prime</a>
%t Select[Range[2500], PrimeQ[121*2^# - 1] &] (* _Michael De Vlieger_, Dec 10 2020 *)
%Y Cf. A032410.
%K hard,nonn
%O 1,2
%A _N. J. A. Sloane_, Dec 29 1999
%E More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 02 2008
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