login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A138603 Numbers n such that 2^(2*n-43)-43 is prime. 0
22, 24, 36, 60, 1678 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..5.

EXAMPLE

2^(2*36-43)-43=536870869, 2^(2*60-43)-43=151115727451828646838229, ...

MATHEMATICA

q=43; For[i=q, i<=q, a={}; Do[x=2^(2*n-i)-i; If[PrimeQ[x], AppendTo[a, n]], {n, 13^3}]; Print["2^(2*n-", i, ")-", i, " ", a]; i=i+2]

Select[Range[1680], PrimeQ[2^(2#-43)-43]&] (* Harvey P. Dale, Apr 25 2020 *)

PROG

(PARI) is(n)=isprime(2^(2*n-43)-43) \\ Charles R Greathouse IV, Jun 13 2017

CROSSREFS

Sequence in context: A030593 A235807 A244397 * A181454 A155911 A061411

Adjacent sequences:  A138600 A138601 A138602 * A138604 A138605 A138606

KEYWORD

nonn,easy

AUTHOR

Vladimir Joseph Stephan Orlovsky, May 13 2008

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified January 21 22:25 EST 2021. Contains 340359 sequences. (Running on oeis4.)