A160600 Numbers k such that 3*(2k)^(2k)+1 is prime.
1, 2, 3, 5, 143, 225
Offset: 1
Examples
a(1) = 1, because 2^2*3+1 = 13 is the smallest prime of this form. a(2) = 2, because 4^4*3+1 = 769 is the next smallest prime of this form. a(3) = 3, because 6^6*3+1 = 139969 is again a prime.
Crossrefs
Programs
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Maple
q:= k-> isprime(3*(2*k)^(2*k)+1): select(q, [$1..225])[]; # Alois P. Heinz, Aug 04 2025
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PARI
for(i=1,9999,ispseudoprime(i^i*3+1)&print1(i/2,","))
Comments