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Numbers k such that 10^k - 987654321 is prime.
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%I #21 Dec 05 2019 17:25:47

%S 986,1240,1928,4054,14252,47528,101728

%N Numbers k such that 10^k - 987654321 is prime.

%C Note that 987654321 is the largest pandigital number in base-10, omitting 0.

%t Select[Range[10000], PrimeQ[10^# - 987654321] &] (* _Robert Price_, Dec 05 2019 *)

%o (PARI) for(n=1,10^4,if(ispseudoprime(10^n-987654321),print1(n,", ")))

%Y Cf. A248349, A248350, A248351, A050289.

%K nonn,hard,more

%O 1,1

%A _Derek Orr_, Oct 05 2014

%E a(6)-a(7) from _Robert Price_, Dec 05 2019