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[ 3^n + n ], Print[ n ] ], {n, 0, 3000} ]
v={2}; Do[If[EvenQ[n]&&Mod[n, 3]!=0&&!PrimeQ[n+1]&&PrimeQ[3^n+n], v=Append[v, n]; Print[v]], {n, 3, 19000}]
Select[Range[18500],PrimeQ[3^#+#]&] (* Harvey P. Dale, Jul 23 2013 *)
is(n)=ispseudoprime(3^n+n) \\ Charles R Greathouse IV, May 22 2017
For k = 3, 4^3 + 3 = 67 is prime.
Select[Table[4^n+n,{n,1,251,2}],PrimeQ] (* Harvey P. Dale, Jun 05 2014 *)
f(n) = for(x=1,n,y=2^x+x;if(isprime(y),print1(y",")))
Select[Range[35000], PrimeQ[5^# + #] &] (* Nico Puada, Apr 24 2025 *)
For[n = 1, n < 5000, n++, If[Not[PrimeQ[n]], If[PrimeQ[4^n + n], Print[n]]]] (Steinerberger) Select[Range[2,10000],!PrimeQ[#]&&PrimeQ[4^#+#]&] (* Harvey P. Dale, Mar 09 2014 *)
\\ p^q + q is prime q not prime
ptoqpq(p,n)= { local(x,y,q); for(q=6,n, if(q%2, if(!isprime(q), y=p^q+q; if(ispseudoprime(y),print1(q",")) ) ) ) }
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