A138596 Numbers n such that 2^(2*n-25)-25 is prime.

13, 14, 15, 16, 17, 19, 29, 31, 41, 44, 59, 76, 77, 95, 107, 197

Offset

1,1

Links

Table of n, a(n) for n=1..16.

Example

2^(2*16-25)-25=103, 2^(2*17-25)-25=487, 2^(2*19-25)-25=8167, ...

Mathematica

q=25; 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]

Prog

(PARI) is(n)=isprime(2^(2*n-25)-25) \\ Charles R Greathouse IV, Jun 13 2017

Crossrefs

Sequence in context: A296745 A178402 A132580 * A293831 A118140 A108854

Adjacent sequences: A138593 A138594 A138595 * A138597 A138598 A138599

Keyword

nonn,easy

Author

Vladimir Joseph Stephan Orlovsky, May 13 2008

Status

approved