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!)
A096594 Numbers n such that 100^n + 10^n - 1 is prime. 5
1, 2, 3, 5, 6, 7, 9, 13, 26, 42, 153, 188, 204, 282, 699, 2886, 11597 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

a(1) through a(17) have been proved to be prime with WinPFGW or pfgw.

a(18) > 20000. - Giovanni Resta, Feb 19 2013

a(18) > 100000. - James G. Merickel Jun 02 2014

LINKS

Table of n, a(n) for n=1..17.

EXAMPLE

a(3) = 3 because 100^3 + 10^3 - 1 = 1000999, a prime.

MATHEMATICA

Select[Range[700], PrimeQ[100^# + 10^# - 1] & ] (* Giovanni Resta, Feb 19 2013 *)

PROG

(PARI) is(n)=ispseudoprime(100^n+10^n-1) \\ Charles R Greathouse IV, Feb 20 2017

CROSSREFS

Sequence in context: A292938 A056900 A226808 * A100693 A030159 A030161

Adjacent sequences:  A096591 A096592 A096593 * A096595 A096596 A096597

KEYWORD

more,nonn

AUTHOR

Jason Earls, Aug 13 2004

EXTENSIONS

a(17) from Giovanni Resta, Feb 19 2013

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 August 8 19:03 EDT 2020. Contains 336298 sequences. (Running on oeis4.)