%I #9 Dec 15 2017 17:36:48
%S 2395,3980,4584,9073,12115
%N Numbers n such that 1_100.2_200.3_300 ... 8_800.9_900.10^n+1 is prime, i.e., 1 repeated 100 times, concatenated with 2 repeated 200 times, etc.
%C These are "subscript" primes, similar to those listed in Table 30 of the Primal Configurations document. All have been proved prime. Primality proof for the largest (16615 digits): PFGW Version 20041001.Win_Stable (v1.2 RC1b) [FFT v23.8] Primality testing (r(100,1)*10^4400+r(200,2)*10^4200+r(300,3)*10^3900+r(400,4)*10^3500+r(500,5)*10^3000+r(600,6)*10^2400+r(700,7)*10^1700+r(800,8)*10^900+r(900,9))*10^12115+1 [N-1, Brillhart-Lehmer-Selfridge] Running N-1 test using base 13 Calling Brillhart-Lehmer-Selfridge with factored part 50.97% (r(100,1)*10^4400+r(200,2)*10^4200+r(300,3)*10^3900+r(400,4)*10^3500+r(500,5)*10^3000+r(600,6)*10^2400+r(700,7)*10^1700+r(800,8)*10^900+r(900,9))*10^12115+1 is prime! (46.2683s+0.0076s)
%H R. Ondrejka, <a href="http://www.utm.edu/research/primes/lists/top_ten/">The Top Ten: a Catalogue of Primal Configurations</a>.
%Y Cf. A106488.
%K base,nonn,more
%O 1,1
%A _Jason Earls_, Jun 02 2005