A125706 Numbers k such that 6^k + 3^k + 2^k = A074528(k) is a prime.

0, 1, 3, 9, 13, 25, 27, 29, 95, 107, 153, 159, 675, 1633, 1693, 2337, 25998, 64289

Offset: 1

Author

Alexander Adamchuk, Jan 31 2007

Keywords

• hard
• more
• nonn

Comments

Corresponding primes of the form 6^k + 3^k + 2^k are {3, 11, 251, 10097891, 13062296531, 28430288877251865251, 1023490376703200952251, 36845653355419807219091, 84017312692910353150294530243640676594723260464784043666542128557055486251, ...}.

Crossrefs

Cf. A074528.

Programs

Mathematica

Do[f=6^n+3^n+2^n;If[PrimeQ[f],Print[{n,f}]],{n,1,675}]

Extensions

More terms from Ryan Propper, Mar 30 2007

a(18) from Michael S. Branicky, Jul 28 2024