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Numbers k such that 2^(2*(k+1)) + 2^k + 1 is prime.
1

%I #15 Sep 08 2022 08:45:17

%S 1,5,9,49,61,81,149,413,485,661,709,1337,2885,2925,3013,7213,9669,

%T 10245

%N Numbers k such that 2^(2*(k+1)) + 2^k + 1 is prime.

%H Steven Harvey, <a href="http://harvey563.tripod.com/InverseCarol.txt">Inverse Carol Primes</a>

%e 2^4 + 2^1 + 1 = 19 is prime so a(1)=1.

%e 2^12 + 2^5 + 1 = 4129 is prime so a(2)=5.

%o (PARI) is(n)=ispseudoprime(2^(2*(n+1))+2^n+1) \\ _Charles R Greathouse IV_, Jun 13 2017

%o (Magma) [k: k in [0..200] | IsPrime(2^(2*(k+1))+2^k+1)]; // _Jinyuan Wang_, Mar 20 2020

%Y Cf. A105181.

%K nonn,more

%O 1,2

%A _Pierre CAMI_, Apr 11 2005

%E More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 05 2008