A090873 a(n) is the smallest number m such that n^2^k + m^2^k is prime for k=0,1,2,3 and 4.

1, 1, 218368, 9324385, 6628674, 601, 365082, 532253, 449140, 4193407, 175746, 2857547, 2752708, 6315245, 80612, 3354745, 10892, 953, 6577504, 157437, 2247676, 11357637, 7650, 272935, 318784, 8034141, 1158380, 22315, 610550, 340357

Offset: 1

Author

Farideh Firoozbakht, Feb 06 2004

Keywords

• nonn

Examples

			a(2)=1 because 2^2^k + 1 is prime for k= 0,1,2,3 and 4.
		

Links

• Kellen Shenton, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A090872, A019434, A000215.

Programs

Mathematica

a[n_] := (For[m=1, !(PrimeQ[m+n]&&PrimeQ[m^2+n^2]&&PrimeQ[m^4+n^4]&& PrimeQ[m^8+n^8]&&PrimeQ[m^16+n^16]), m++ ];m);Do[Print[a[n]], {n, 50}]

Formula

a[n_] := (For[m=1, !(PrimeQ[m+n]&&PrimeQ[m^2+n^2]&&PrimeQ[m^4+n^4]&& PrimeQ[m^8+n^8]&&PrimeQ[m^16+n^16]), m++ ];m)