1,1

Table of n, a(n) for n=1..26.

910109 is prime and of the form 9nn9 for n=10.

9101310139 is prime and of the form 9nn9 for n=1013.

Cf. A102484 for sequence of all numbers of form 9nn9. A102502 for the n values corresponding to the primes in this sequence.

Sequence in context: A015333 A141461 A035793 * A251908 A186608 A236617

Adjacent sequences: A102500 A102501 A102502 * A102504 A102505 A102506

easy,nonn,base

Mark Hudson (mrmarkhudson(AT)hotmail.com), Jan 13 2005

approved