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%I M2481 #23 Jun 17 2020 02:23:17
%S 1,3,5,11,19,29,157,163,283,379,997,10141,14699,77291,85237,106693,
%T 203789,3704053
%N Numbers n such that 2^n + 2^(n + 1)/2 + 1 is prime.
%D J. Brillhart et al., Factorizations of b^n +- 1. Contemporary Mathematics, Vol. 22, Amer. Math. Soc., Providence, RI, 2nd edition, 1985; and later supplements.
%D N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
%H J. Brillhart et al., <a href="http://dx.doi.org/10.1090/conm/022">Factorizations of b^n +- 1</a>, Contemporary Mathematics, Vol. 22, Amer. Math. Soc., Providence, RI, 3rd edition, 2002.
%H S. S. Wagstaff, Jr., <a href="http://www.cerias.purdue.edu/homes/ssw/cun/index.html">The Cunningham Project</a>
%o (PARI) is(n)=ispseudoprime(2^n+2^(n+1)/2+1) \\ _Charles R Greathouse IV_, Feb 17 2017
%Y Cf. A057429.
%K nonn,hard,more
%O 1,2
%A _N. J. A. Sloane_, _Robert G. Wilson v_
%E More terms from _Robert G. Wilson v_, Sep 07 2000
%E 203789 found and proved prime by _Mike Oakes_, on Sep 28 2000.
%E a(18) from _Serge Batalov_, Jun 16 2020
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