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Numbers n such that 101101 * 10^n + 1 is prime.
1

%I #10 Dec 15 2017 17:36:47

%S 5,6,7,12,21,25,300,305,600,689,742,1418,1547,1744,5275,6355,7477,

%T 15312,16772,33047

%N Numbers n such that 101101 * 10^n + 1 is prime.

%C These are anti-Yarborough primes, i.e. primes containing just 1's and 0's and they have all been certified. Primality proof for the largest: PFGW Version 20041001.Win_Stable (v1.2 RC1b) [FFT v23.8] Primality testing 101101*10^33047+1 [N-1, Brillhart-Lehmer-Selfridge] Running N-1 test using base 3 Calling Brillhart-Lehmer-Selfridge with factored part 69.89% 101101*10^33047+1 is prime! (194.9694s+0.0907s)

%H R. Ondrejka, <a href="http://www.utm.edu/research/primes/lists/top_ten/">The Top Ten: a Catalogue of Primal Configurations</a>.

%o (PARI) is(n)=ispseudoprime(101101*10^n+1) \\ _Charles R Greathouse IV_, Jun 06 2017

%Y Cf. A020449.

%K nonn,more

%O 1,1

%A _Jason Earls_, May 16 2005