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Primes of the form 10^n-9^n
2

%I #8 Sep 08 2022 08:46:00

%S 19,271,5217031,68618940391,8649148282327007911,

%T 95289871302753755165078396311

%N Primes of the form 10^n-9^n

%H Vincenzo Librandi, <a href="/A199819/b199819.txt">Table of n, a(n) for n = 1..9</a>

%t Select[10^Range[3000]-9^Range[3000],PrimeQ]

%o (Magma) [ a: n in [0..400] | IsPrime(a) where a is 10^n-9^n ]

%Y Cf. A016189, A062576

%K nonn

%O 1,1

%A _Vincenzo Librandi_, Nov 21 2011