A138600 Numbers k such that 2^(2*k-33) - 33 is prime.

21, 31, 55, 85, 91, 121, 159, 175, 379, 555, 769, 1761, 3375, 4881, 5121, 6089, 10659, 13129, 20049, 33021

Offset

1,1

Comments

a(21) > 70000. - Michael S. Branicky, May 21 2026

Links

Table of n, a(n) for n=1..20.

Example

2^(2*21-33)-33 = 479, 2^(2*31-33)-33 = 536870879, 2^(2*55-33)-33 = 151115727451828646838239, ... .

Mathematica

q=33; For[i=q, i<=q, a={}; Do[x=2^(2*n-i)-i; If[PrimeQ[x], AppendTo[a, n]], {n, 10^3}]; Print["2^(2*n-", i, ")-", i, " ", a]; i=i+2]

Prog

(PARI) is(n)=isprime(2^(2*n-33)-33) \\ Charles R Greathouse IV, Jun 13 2017

Crossrefs

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

Cf. A138598, A138599, A138601, A138602, A138603.

Sequence in context: A032585 A138822 A104297 * A106324 A208293 A032013

Adjacent sequences: A138597 A138598 A138599 * A138601 A138602 A138603

Keyword

nonn,more

Author

Vladimir Joseph Stephan Orlovsky, May 13 2008

Extensions

Term 17 removed and a(12)-a(20) from Michael S. Branicky, May 20 2026

Status

approved