A250481 Primes of the form 2^x + y^2 with x, y > 0.

3, 5, 11, 13, 17, 29, 41, 53, 73, 83, 89, 97, 113, 137, 173, 227, 229, 233, 241, 257, 281, 293, 337, 353, 443, 449, 457, 521, 569, 593, 617, 641, 733, 761, 857, 881, 953, 977, 1033, 1049, 1091, 1093, 1097, 1153, 1193, 1217, 1229, 1249, 1289, 1373

Offset

1,1

Links

Table of n, a(n) for n=1..50.

Example

11 is in the sequence because 2^1+3^2 = 11.
97 is in the sequence because 2^4+9^2 = 97.

Mathematica

f[x_, y_]:=2^x + y^2; lst={}; Do[p=f[x, y]; If[PrimeQ[p], AppendTo[lst, p]], {y, 50}, {x, 50}]; Take[Union[lst], 50]

Crossrefs

Cf. A248346.

Cf. primes of the type k^x+y^k: this sequence (k=2), A250716 (k=3), A250717 (k=4), A250842 (k=5), A250843 (k=6), A250844 (k=7).

Sequence in context: A062391 A038951 A020578 * A227011 A243627 A178604

Adjacent sequences: A250478 A250479 A250480 * A250482 A250483 A250484

Keyword

nonn

Author

Vincenzo Librandi, Nov 24 2014

Status

approved