A162573 Primes of the form 2^x+x*y+2^y, with x and y integers of any sign.

2, 3, 5, 13, 17, 89, 137, 157, 257, 523, 547, 2089, 2659, 4217, 8821, 16553, 34981, 65537, 65761, 262433, 524309, 524353, 524971, 2097223, 2097289, 2097427, 2099431, 8390909, 10486243, 35652109, 134217757, 536871089, 536873279

Offset

1,1

Comments

Allowing either sign in x or y leads to fractions 2^x or 2^y if x or y are negative,

but since the sum must be integer, only the case x=y=-1 matters in these quadrants. - R. J. Mathar, Jul 31 2007

Links

Table of n, a(n) for n=1..33.

Mathematica

f[x_, y_]:=2^x+x*y+2^y; lst={}; Do[Do[p=f[x, y]; If[PrimeQ[p], AppendTo[lst, p]], {y, -5!, 6!}], {x, -5!, 6!}]; Take[Union[lst], 5! ]

Crossrefs

Sequence in context: A108562 A087523 A073919 * A349785 A087356 A281598

Adjacent sequences: A162570 A162571 A162572 * A162574 A162575 A162576

Keyword

nonn

Author

Vladimir Joseph Stephan Orlovsky, Jul 06 2009

Status

approved