This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
a(2)=7 because 6^7 - 7^6 = 162287 is prime.
Do[If[PrimeQ[(6^n-n^6)],Print[n]],{n,1,3000}]
for(x=1,1e5,ispseudoprime(p=6^x-x^6)&&print1(x", ")) \\ M. F. Hasler, Aug 20 2014
lst={};k=7;Do[If[PrimeQ[Abs[k^n-n^k]], AppendTo[lst, n]], {n, 0, 10^4}];lst (* Vladimir Joseph Stephan Orlovsky, Sep 10 2008 *)
is(n)=isprime(abs(7^n-n^7)) \\ Charles R Greathouse IV, Feb 17 2017
lst={};k=9;Do[If[PrimeQ[Abs[k^n-n^k]], AppendTo[lst, n]], {n, 0, 10^4}];lst (* Vladimir Joseph Stephan Orlovsky, Sep 10 2008 *)
is(n)=isprime(abs(9^n-n^9)) \\ Charles R Greathouse IV, Feb 17 2017
[n: n in [0..500]| IsPrime(10^n-n^10)]; // Vincenzo Librandi, Apr 01 2015
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 *)
is(n)=isprime(abs(10^n-n^10)) \\ Charles R Greathouse IV, Feb 17 2017
lst={};k=11;Do[If[PrimeQ[Abs[k^n-n^k]], AppendTo[lst, n]], {n, 0, 10^4}];lst (* Vladimir Joseph Stephan Orlovsky, Sep 10 2008 *)
is(n)=ispseudoprime(abs(11^n-n^11)) \\ Charles R Greathouse IV, Feb 17 2017
Do[If[PrimeQ[Abs[14^n - n^14]], Print[n]], {n, 10^4}] (* Ryan Propper, Mar 27 2007 *)
is(n)=ispseudoprime(abs(14^n-n^14)) \\ Charles R Greathouse IV, Feb 17 2017
2^1-1^2 = 1 is not prime. 2^2-2^2 = 0 is not prime. 2^3-3^2 = -1 is not prime. 2^4-4^2 = 0 is not prime. 2^5-5^2 = 7 is prime. So a(2) = 5.
a(n)=k=1; if(n>4, forprime(p=1, 100, if(ispower(n)&&ispower(n)%p==0&&n%p==0, return(0)); if(n%p==n, break))); k=1; while(!ispseudoprime(n^k-k^n), k++); return(k) vector(15, n, a(n+1))
import sympy
from sympy import isprime
from sympy import gcd
def Min(x):
k = 1
while k < 5000:
if gcd(k,x) == 1:
if isprime(x**k-k**x):
return k
else:
k += 1
else:
k += 1
x = 1
while x < 100:
print(Min(x))
x += 1
Select[Table[6^x-x^6,{x,200}],PrimeQ] (* Harvey P. Dale, Jan 17 2018 *)
for(x=1,1e5,ispseudoprime(p=6^x-x^6)&&print1(p","))
Select[Table[n+2^n+3^n,{n,0,6!}],PrimeQ[#]&]
Comments