A145852 Primes of the form k followed by a 0 and k 9's.

109, 2099, 409999, 1909999999999999999999, 2809999999999999999999999999999, 41099999999999999999999999999999999999999999, 7609999999999999999999999999999999999999999999999999999999999999999999999999999

Offset

1,1

Comments

Primes of the form k*10^(k+1) + 10^k - 1.

Links

Table of n, a(n) for n=1..7.

Prog

(PARI) lista(nn) = for(k=1, nn, if(ispseudoprime(q=k*10^(k+1)+10^k-1), print1(q, ", "))); \\ Jinyuan Wang, Mar 24 2020

Crossrefs

Cf. A141311, A145851.

Sequence in context: A232118 A201849 A061724 * A232198 A232416 A333116

Adjacent sequences: A145849 A145850 A145851 * A145853 A145854 A145855

Keyword

nonn

Author

Lekraj Beedassy, Oct 21 2008

Status

approved