VOOZH about

URL: https://oeis.org/A138599

⇱ A138599 - OEIS

login
A138599
Numbers n such that 2^(2*n-31)-31 is prime.
0
16, 17, 19, 21, 22, 24, 25, 33, 34, 36, 46, 49, 60, 70, 90, 93, 112, 137, 143, 207, 216, 263, 280, 477, 647, 1257, 1383
OFFSET
1,1
EXAMPLE
2^(2*19-31)-31=97, 2^(2*21-31)-31=2017, 2^(2*22-31)-31=8161, ...
MATHEMATICA
q=31; For[i=q, i<=q, a={}; Do[x=2^(2*n-i)-i; If[PrimeQ[x], AppendTo[a, n]], {n, 20^2}]; Print["2^(2*n-", i, ")-", i, " ", a]; i=i+2]
Select[Range[1500], PrimeQ[2^(2#-31)-31]&]
PROG
(PARI) is(n)=isprime(2^(2*n-31)-31) \\ Charles R Greathouse IV, Jun 13 2017
CROSSREFS
Sequence in context: A209726 A326455 A145449 * A258265 A261344 A007636
KEYWORD
nonn,easy
AUTHOR
EXTENSIONS
More terms from Harvey P. Dale, Apr 08 2018
STATUS
approved