A128450 Numbers k such that absolute value of 10^k - k^10 is prime.

3, 9, 273, 399

Offset: 1

Author

Alexander Adamchuk, Mar 03 2007

Keywords

• hard
• more
• nonn
• less

Comments

a(5) > 10^5 if it exists. - Michael S. Branicky, Nov 27 2024

Crossrefs

Cf. A072180, A109387, A117705, A117706, A128447, A128448, A128449, A128451, A122003, A128453, A128454.

Programs

Magma

[n: n in [0..500]| IsPrime(10^n-n^10)]; // Vincenzo Librandi, Apr 01 2015

Mathematica

lst={};k=10;Do[If[PrimeQ[Abs[k^n-n^k]], AppendTo[lst, n]], {n, 0, 10^4}];lst (* Vladimir Joseph Stephan Orlovsky, Sep 10 2008 *)
Select[Range[0, 10000], PrimeQ[10^# - #^10] &] (* Vincenzo Librandi, Apr 01 2015 *)

PARI

is(n)=isprime(abs(10^n-n^10)) \\ Charles R Greathouse IV, Feb 17 2017