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.
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
a(2) = 8023 because 8023 = 71*113 = 2^13 - 13^2 = 2^A099481(2) - A099481(2)^2.
Select[Table[2^n - n^2, {n, 100}], PrimeOmega[#] == 2&] (* Vincenzo Librandi, Sep 21 2012 *)
4 is in the sequence because the 4th prime is 7 and 2^7 - 7^2 = 79 is a prime.
a:=proc(n) if isprime(2^ithprime(n)-ithprime(n)^2) then n else fi end: seq(a(n),n=1..400); # Emeric Deutsch, Apr 06 2006
Select[Range[1200], PrimeQ[2^# - #^2] &@ Prime@ # &] (* Michael De Vlieger, Feb 02 2019 *)
for(i=1,100,if(isprime(2^prime(i)-prime(i)^2),print1(i,",")))
a(1) = 11 because 2^11 - 11^2 = 1927 = 41*47.
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","))
a:= n-> max(numtheory[factorset]((p-> 2^p-p^2)(ithprime(n)))): seq(a(n), n=3..27); # Alois P. Heinz, Mar 03 2022
a[n_] := FactorInteger[2^(p = Prime[n]) - p^2][[-1, 1]]; Array[a, 25, 3] (* Amiram Eldar, Mar 03 2022 *)
a(n) = my(p=prime(n)); vecmax(factor(2^p - p^2)[,1]); \\ Michel Marcus, Mar 03 2022
a(0)=0 because [2^0-0^2, 2^0]=[1, 1], a(1)=1 because 2 in range [2^1-1^2, 2^1]=[1, 2], a(2)=2 because 2, 3 in range [2^2-2^2, 2^2]=[0, 4], a(3)=4 because 2, 3, 5, 7 in range [2^3-3^2, 2^3]=[-1, 8], a(4)=6 because 2, 3, 5, 7, 11, 13 in range [2^4-4^2, 2^4]=[0, 16], a(5)=8 because 7, 11, 13, 17, 19, 23, 29, 31 in range [2^5-5^2, 2^5]=[7, 32].
A192515 := proc(n) a := 0 ; for i from 2^n-n^2 to 2^n do if isprime(i) then a := a+1 ; end if; end do; a ; end proc: # R. J. Mathar, Jul 11 2011
Table[Count[Range[2^n - n^2, 2^n], p_ /; PrimeQ@ p], {n, 0, 65}] (* Michael De Vlieger, Apr 03 2016 *)
a(n) = primepi(2^n) - primepi(2^n-n^2) + isprime(2^n-n^2); \\ Michel Marcus, Apr 03 2016
5 is in this sequence because 5 and 2^5 - 5^2 = 7 are both prime.
[p: p in PrimeUpTo(2200) | IsPrime(2^p - p^2)];
select(p -> isprime(p) and isprime(2^p - p^2), {2} union {seq(2*i+1,i=1..2000)});# Robert Israel, Jun 10 2014
Select[Prime[Range[300]], PrimeQ[2^# - #^2] &] (* Alonso del Arte, May 27 2014 *)
isok(p) = isprime(p) && ispseudoprime(2^p - p^2); \\ Daniel Suteu, Jun 25 2022
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