%I #8 Mar 24 2020 08:43:39
%S 109,2099,409999,1909999999999999999999,
%T 2809999999999999999999999999999,
%U 41099999999999999999999999999999999999999999,7609999999999999999999999999999999999999999999999999999999999999999999999999999
%N Primes of the form k followed by a 0 and k 9's.
%C Primes of the form k*10^(k+1) + 10^k - 1.
%o (PARI) lista(nn) = for(k=1, nn, if(ispseudoprime(q=k*10^(k+1)+10^k-1), print1(q, ", "))); \\ _Jinyuan Wang_, Mar 24 2020
%Y Cf. A141311, A145851.
%K nonn
%O 1,1
%A _Lekraj Beedassy_, Oct 21 2008