A138577 Numbers n such that 2^(2*n-3)-3 is prime.

3, 4, 6, 16, 108, 112, 118, 274, 346, 1162, 1620

Offset

1,1

Links

Table of n, a(n) for n=1..11.

Example

2^(2*3-3)-3=5, 2^(2*4-3)-3=29, 2^(2*6-3)-3=509,...

Mathematica

q=3; For[i=q, i<=q, a={}; Do[x=2^(2*n-i)-i; If[PrimeQ[x], AppendTo[a, n]], {n, 10^2}]; Print["2^(2*n-", i, ")-", i, " ", a]; i=i+2]
Select[Range[400], PrimeQ[2^(2#-3)-3]&] (* Harvey P. Dale, Aug 10 2017 *)

Prog

(PARI) is(n)=isprime(2^(2*n-3)-3) \\ Charles R Greathouse IV, Jun 13 2017

Crossrefs

Sequence in context: A092933 A122849 A068573 * A298149 A136242 A066732

Adjacent sequences: A138574 A138575 A138576 * A138578 A138579 A138580

Keyword

nonn,easy

Author

Vladimir Joseph Stephan Orlovsky, May 13 2008

Extensions

More terms from Harvey P. Dale, Aug 10 2017

Status

approved