A081506 Primes of the form 2^k + 3^k + 4^k.

3, 29, 353, 4889, 72353, 105312291668560568089831550410013687058921146068446092937783402353

Offset

1,1

Comments

The next term (a(7)) has 202 digits. - Harvey P. Dale, Aug 20 2015

Links

Amiram Eldar, Table of n, a(n) for n = 1..9

Formula

a(n) = A074526(A081507(n)). - Amiram Eldar, Aug 17 2024

Example

k = 2: 2^2 + 3^2 + 4^2 = 4 + 9 + 16 = 29, which is prime.

Mathematica

Do[s=2^w+3^w+4^w; If[IntegerQ[w/100], Print[{w}]]; If[PrimeQ[s], Print[{w, s}]], {w, 0, 1000}]
Select[Table[2^n+3^n+4^n, {n, 0, 200}], PrimeQ] (* Harvey P. Dale, Aug 20 2015 *)

Prog

(PARI) lista(kmax) = {my(p); for(k = 0, kmax, p = 2^k + 3^k + 4^k; if(isprime(p), print1(p, ", "))); } \\ Amiram Eldar, Aug 17 2024

Crossrefs

Cf. A074526, A081507.

Sequence in context: A323569 A049038 A091646 * A168127 A361220 A262640

Adjacent sequences: A081503 A081504 A081505 * A081507 A081508 A081509

Keyword

nonn

Author

Labos Elemer, Apr 15 2003

Status

approved