A138602 Numbers k such that 2^(2*k-39) - 39 is prime.

23, 32, 33, 83, 140, 1122, 5052, 19697, 22472, 38673, 73128

Offset

1,1

Links

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

Example

2^(2*23-39)-39 = 89, 2^(2*32-39)-39 = 33554393, 2^(2*33-39)-39 = 134217689, 2^(2*83-39)-39 = 170141183460469231731687303715884105689, ... .

Mathematica

q=39; For[i=q, i<=q, a={}; Do[x=2^(2*n-i)-i; If[PrimeQ[x], AppendTo[a, n]], {n, 12^3}]; Print["2^(2*n-", i, ")-", i, " ", a]; i=i+2]

Prog

(PARI) is(n)=isprime(2^(2*n-39)-39) \\ Charles R Greathouse IV, Jun 13 2017

Crossrefs

Cf. A138577, A138578, A138579, A138580, A138581, A138582.

Cf. A138598, A138599, A138600, A138601, A138603.

Sequence in context: A130825 A087563 A093477 * A070664 A243907 A096083

Adjacent sequences: A138599 A138600 A138601 * A138603 A138604 A138605

Keyword

nonn,more

Author

Vladimir Joseph Stephan Orlovsky, May 13 2008

Extensions

Terms 20, 21 and 22 removed and a(7)-a(11) from Michael S. Branicky, May 21 2026

Status

approved