A114301 Numbers k such that 2^k + 3^k + 5^k + 7^k is a prime number.
1, 3, 19, 1013, 4133, 9833, 30809, 64459
Offset: 1
Examples
2^3 + 3^3 + 5^3 + 7^3 = 503 (prime), thus 3 is in the sequence.
Crossrefs
Cf. A135168.
Programs
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Maple
select(t -> isprime(2^t+3^t+5^t+7^t), [seq(i,i=1..10000,2)]); # Robert Israel, May 03 2018
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Mathematica
Do[If[PrimeQ[2^n+3^n+5^n+7^n], Print[n]], {n,1,5000}]
Extensions
a(6) from Ryan Propper, Mar 24 2006
a(7) from Joao Carlos Leandro da Silva (zxawyh66(AT)yahoo.com), Jun 01 2009
a(8) from Michael S. Branicky, Jun 04 2024
Comments