A087557 a(n) = smallest prime that is the concatenation of two numbers whose product is n.

11, 0, 13, 41, 0, 23, 17, 0, 19, 101, 0, 43, 113, 0, 53, 0, 0, 29, 191, 0, 37, 211, 0, 83, 251, 0, 127, 47, 0, 103, 131, 0, 113, 0, 0, 0, 137, 0, 139, 401, 0, 67, 431, 0, 59, 223, 0, 163, 149, 0, 151, 521, 0, 227, 0, 0, 157, 229, 0, 601, 0, 0, 79, 641, 0, 223, 167, 0, 233, 107, 0

Offset

2,1

Comments

a(3k+2) = 0. - David Wasserman, Jun 07 2005

Links

Table of n, a(n) for n=2..72.

Example

a(10) = 101, the pair of complementary factors of 10 are (1,10), (2,5) and the primes obtained are 101.

Crossrefs

Cf. A087558.

Sequence in context: A147765 A087556 A082268 * A186072 A299780 A297873

Adjacent sequences: A087554 A087555 A087556 * A087558 A087559 A087560

Keyword

base,nonn

Author

Amarnath Murthy, Sep 13 2003

Extensions

More terms from David Wasserman, Jun 07 2005

Status

approved