A250717 Primes of the form 4^x + y^4 with x, y > 0.

5, 17, 97, 257, 337, 641, 881, 2417, 2657, 4177, 4721, 6577, 10657, 14657, 14897, 28817, 54721, 65537, 65617, 66161, 80177, 83537, 83777, 130337, 134417, 149057, 260017, 279857, 280097, 283937, 394721, 531457, 596977, 1049201, 1050977, 1055137, 1178897

Offset: 1

Author

Vincenzo Librandi, Nov 27 2014

Keywords

• nonn
• less

Comments

Subsequence of A250481. Also, except for the first term, subsequence of A002645.

Examples

			257 is in this sequence because 4^4+1^4=257.
881 is in this sequence because 4^4+5^4=881.
		

Crossrefs

Cf. A250545.

Cf. similar sequences listed in A250481.

Programs

Mathematica

f[x_, y_]:= 4^x + y^4; lst={}; Do[p=f[x, y]; If[PrimeQ[p], AppendTo[lst, p]], {y, 50}, {x, 50}]; Take[Union[lst], 50]