A147554 Primes p such that p^2 divides p.p.p where dot "." means concatenation.

3, 13, 37, 9901, 333667, 99990001, 999999000001, 9999999900000001, 13168164561429877, 130654897808007778425046117

Offset: 1

Author

Farideh Firoozbakht, Dec 26 2008

Keywords

• nonn
• base
• more

Comments

Primes p dividing 10^(2*d)+10^d+1 where d=ceiling(log(p)/log(10)) is the number of decimal digits in p. - Max Alekseyev

There is no prime p such that p^2 divides p.p.

All primes of the forms 10^(2m) - 10^m + 1 or (1/3)*(10^(2m) + 10^m + 1) are in the sequence.

Primes in A243162. - Hans Havermann, May 31 2014

a(11) > 10^158. - Max Alekseyev, Sep 11 2024

Crossrefs

Cf. A147553, A243162.