%I M2145 N0854 #43 Nov 06 2023 14:58:04
%S 2,26,50,54,126,134,246,354,362,950,1310,2498,6926,11826,31734,67850,
%T 74726,96150,374114,696438,743322,1044086,1104606,1261478
%N Numbers k such that 11*2^k - 1 is prime.
%D H. Riesel, "Prime numbers and computer methods for factorization", Progress in Mathematics, Vol. 57, Birkhäuser, Boston, 1985, Chap. 4, see pp. 381-384.
%D N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
%D N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
%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 H. C. Williams and C. R. Zarnke, <a href="http://dx.doi.org/10.1090/S0025-5718-1968-0227095-2">A report on prime numbers of the forms M = (6a+1)*2^(2m-1)-1 and (6a-1)*2^(2m)-1</a>, Math. Comp., 22 (1968), 420-422.
%H <a href="/index/Pri#riesel">Index entries for sequences of n such that k*2^n-1 (or k*2^n+1) is prime</a>
%o (PARI) is(n)=ispseudoprime(11*2^n-1) \\ _Charles R Greathouse IV_, Feb 20 2017
%o (Python)
%o from sympy import isprime
%o def aupto(lim): return [k for k in range(1, lim+1) if isprime(11*2**k - 1)]
%o print(aupto(2500)) # _Michael S. Branicky_, Feb 26 2021
%Y Cf. A050525.
%Y Cf. A002261 (11*2^k+1 is prime).
%K hard,nonn,nice,more
%O 1,1
%A _N. J. A. Sloane_
%E More terms from _Hugo Pfoertner_, Jun 23 2004
%E More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 02 2008