A277122 Primes of the form 5^k + 3^k - 1.

7, 151, 1972807, 1818989407598411628849054391, 21382117680737565169124291737211855035830505403680318251383549467509816267540836044857784735512271804718726595516967

Offset: 1

Author

Alex Ratushnyak, Sep 30 2016

Keywords

• nonn

Comments

The sequence of corresponding k starts: 1, 3, 9, 39, 165 (A180741).

Primes in A155603. - Altug Alkan, Oct 01 2016

Crossrefs

Cf. A000040, A081508, A155603, A180741.

Programs

Mathematica

Select[Table[5^k + 3^k - 1, {k, 0, 200}], PrimeQ] (* Amiram Eldar, Aug 11 2024 *)

PARI

lista(kmax) = {my(p); for(k = 0, kmax, p = 5^k + 3^k - 1; if(isprime(p), print1(p, ", ")));} \\ Amiram Eldar, Aug 11 2024

Formula

a(n) = A155603(A180741(n)). - Amiram Eldar, Aug 11 2024