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

1,1

Comments

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

Links

Table of n, a(n) for n=1..37.

Example

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

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]

Crossrefs

Cf. A250545.

Cf. similar sequences listed in A250481.

Sequence in context: A262862 A367921 A180382 * A287842 A254759 A139390

Adjacent sequences: A250714 A250715 A250716 * A250718 A250719 A250720

Keyword

nonn,less

Author

Vincenzo Librandi, Nov 27 2014

Status

approved