A087555 a(n) = largest prime that is the concatenation of two numbers whose sum is n.

11, 0, 31, 41, 0, 61, 71, 0, 73, 101, 0, 211, 311, 0, 313, 107, 0, 811, 911, 0, 211, 1013, 0, 1213, 1511, 0, 1117, 1811, 0, 2011, 2111, 0, 2311, 2411, 0, 2017, 2711, 0, 2713, 3011, 0, 2617, 431, 0, 3511, 3413, 0, 3613, 3911, 0, 4111, 4211, 0, 541, 3917, 0, 4513, 4217

Offset

2,1

Comments

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

Links

Table of n, a(n) for n=2..59.

Example

a(10) = 73, 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. A087556.

Sequence in context: A075360 A256756 A087558 * A185682 A217752 A335646

Adjacent sequences: A087552 A087553 A087554 * A087556 A087557 A087558

Keyword

base,nonn

Author

Amarnath Murthy, Sep 13 2003

Extensions

More terms from David Wasserman, Jun 07 2005

Status

approved