A087556 - OEIS

A087556

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

11, 0, 13, 23, 0, 43, 17, 0, 19, 29, 0, 67, 59, 0, 79, 89, 0, 109, 137, 0, 139, 149, 0, 223, 179, 0, 127, 227, 0, 229, 131, 0, 277, 233, 0, 307, 137, 0, 139, 239, 0, 241, 359, 0, 379, 389, 0, 409, 149, 0, 151, 251, 0, 487, 353, 0, 157, 257, 0, 457, 359, 0, 163, 263, 0, 463

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OFFSET

2,1

COMMENTS

a(3k) = 0. Conjecture: No other term is zero.

LINKS

Table of n, a(n) for n=2..67.

EXAMPLE

a(10) = 19, the Partitions of 10 are (1,9), (2,8), 3,7), (4,6), (5,5) and the primes obtained are 19,37 and 73.

CROSSREFS

Cf. A087555.

Sequence in context: A271572 A180059 A147765 * A082268 A087557 A186072