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%I #30 Nov 07 2018 10:05:02
%S 1,2,4,18,56,60,88,1288,1784,3406,9250,11968,36216,57206
%N Numbers k such that 4^k - 3^k + 2^k is prime.
%C 1 is the only odd number in this sequence.
%C a(15) > 65432.
%e 4^2 - 3^2 + 2^2 = 16 - 9 + 4 = 11 is prime.
%t Select[Range[0, 5000], PrimeQ[4^# - 3^# + 2^#] &]
%o (PARI) for(n=1, 5000, if(ispseudoprime(4^n-3^n+2^n), print1(n, ", ")))
%Y Cf. A083324, A138699.
%K nonn,more
%O 1,2
%A _Jinyuan Wang_, Aug 09 2018
%E a(13)-a(14) from _Giovanni Resta_, Aug 10 2018
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