A081510 Numbers k such that 1 + 2^k + 4^k + 6^k is prime.

1, 11, 23, 59, 399, 63321

Offset

1,2

Links

Table of n, a(n) for n=1..6.

Example

m=1: 1+2+4+6=13 prime.

Mathematica

Do[s=1^w+2^w+4^w+6^w; If[IntegerQ[w/100], Print[{w}]]; If[PrimeQ[s], Print[{w, s}]], {w, 0, 1000}]
Select[Range[400], PrimeQ[2^#+4^#+6^#+1]&] (* Harvey P. Dale, Jun 03 2023 *)

Prog

(PARI) is(n)=ispseudoprime(1+2^n+4^n+6^n) \\ Charles R Greathouse IV, Jun 13 2017

Crossrefs

Cf. A081509.

Sequence in context: A105967 A097473 A366487 * A068844 A139905 A267437

Adjacent sequences: A081507 A081508 A081509 * A081511 A081512 A081513

Keyword

more,nonn

Author

Labos Elemer, Apr 15 2003

Extensions

a(6) from Michael S. Branicky, Aug 10 2024

Status

approved