A088647 a(1) = 1, then the smallest number such that the concatenation a(r), a(s) is prime for all s > r.

1, 1, 3, 7, 73, 433, 607, 13381, 37279, 4800307

Offset

0,3

Comments

Conjecture: sequence is finite.

Links

Table of n, a(n) for n=0..9.

Example

a(5) = 73 as 173,373,773 are all prime.

Crossrefs

Cf. A075611. [From R. J. Mathar, Sep 11 2008]

Sequence in context: A354891 A354893 A342546 * A075611 A191485 A119572

Adjacent sequences: A088644 A088645 A088646 * A088648 A088649 A088650

Keyword

base,nonn

Author

Amarnath Murthy, Oct 29 2003

Extensions

More terms from David Wasserman, Aug 17 2005

Status

approved