The OEIS is supported by the many generous donors to the OEIS Foundation.

 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 | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified September 12 23:44 EDT 2024. Contains 375855 sequences. (Running on oeis4.)