A138603 Numbers n such that 2^(2*n-43)-43 is prime.

22, 24, 36, 60, 1678

Offset

1,1

Links

Table of n, a(n) for n=1..5.

Example

2^(2*36-43)-43=536870869, 2^(2*60-43)-43=151115727451828646838229, ...

Mathematica

q=43; For[i=q, i<=q, a={}; Do[x=2^(2*n-i)-i; If[PrimeQ[x], AppendTo[a, n]], {n, 13^3}]; Print["2^(2*n-", i, ")-", i, " ", a]; i=i+2]
Select[Range[1680], PrimeQ[2^(2#-43)-43]&] (* Harvey P. Dale, Apr 25 2020 *)

Prog

(PARI) is(n)=isprime(2^(2*n-43)-43) \\ Charles R Greathouse IV, Jun 13 2017

Crossrefs

Sequence in context: A030593 A235807 A244397 * A181454 A155911 A061411

Adjacent sequences: A138600 A138601 A138602 * A138604 A138605 A138606

Keyword

nonn,easy

Author

Vladimir Joseph Stephan Orlovsky, May 13 2008

Status

approved