A076513
Numbers k such that 2 + 2^k + 3^k is prime.
Original entry on oeis.org
1, 3, 5, 65, 119, 213, 1209, 2469, 2669, 3939, 11219
Offset: 1
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Do[ If[ PrimeQ[2 + 2^n + 3^n], Print[n]], {n, 1, 4000, 2}]
Select[Range[10000], PrimeQ[2 + 2^# + 3^#] &] (* _Vincenzo Librandi: Oct 05 2012 *)
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is(n)=ispseudoprime(2+2^n+3^n) \\ Charles R Greathouse IV, Jun 13 2017
Original entry on oeis.org
4, 7, 15, 37, 99, 277, 795, 2317, 6819, 20197, 60075, 179197, 535539, 1602517, 4799355, 14381677, 43112259, 129271237, 387682635, 1162785757, 3487832979, 10462450357, 31385253915, 94151567437, 282446313699, 847322163877, 2541932937195, 7625731702717
Offset: 0
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with(combinat):f:=n-> sum(fibonacci(k)^n,k=0..4):seq(f(n),n=1..20);
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Table[2+2^n+3^n,{n,0,40}] (* or *) LinearRecurrence[{6,-11,6},{4,7,15},40](* Harvey P. Dale, Jun 08 2011 *)
A353102
Primes of the form 2^k + 3^k + 6.
Original entry on oeis.org
11, 19, 41, 103, 281, 6823, 20201, 14381681, 387682639, 94151567441, 282446313703, 5559069156490121, 16677198879535759, 50031579458738081, 984770919775797277303, 1144561273440060866922804472241, 969773729787523912361831763509149540341223, 2909321189362571427600485469182379896242601
Offset: 1
2^1 + 3^1 + 6 = 11, which is a prime.
2^2 + 3^2 + 6 = 19, which is a prime.
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Select[Table[2^n + 3^n + 6,{n,1,1000}],PrimeQ]
Showing 1-3 of 3 results.
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