

A110456


Largest prime obtained by concatenation of parts of a distinct partition of n. 0 if no such number exist.


0



0, 2, 3, 31, 41, 0, 421, 521, 0, 4231, 5231, 0, 7321, 8231, 0, 64231, 74231, 0, 94321, 431021, 0, 754123, 854213, 0, 5431021, 6421013, 0, 8431021, 9431021, 0, 65412103, 75411023, 0, 95421103, 96412103, 0, 643110211, 765324101
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OFFSET

1,2


COMMENTS

Conjecture a(n) = 0 only for n = 1, or n == 0 (mod 3), n is > 3. Subsidiary sequence (hard): Number of primes generated by concatenation of distinct partitions of n.


LINKS

Table of n, a(n) for n=1..38.


EXAMPLE

Distinct partitions of 10 are 10,(9,1), (8,2), (7,3),...(7,2,1),(6,3,1),(5,3,2),...(4,3,2,1), etc. (4231 is the largest number obtained as a concatenation of (4,2,3,1).
a(10)=4231.


CROSSREFS

Sequence in context: A272043 A136150 A155056 * A128348 A029973 A344736
Adjacent sequences: A110453 A110454 A110455 * A110457 A110458 A110459


KEYWORD

base,nonn


AUTHOR

Amarnath Murthy, Aug 04 2005


EXTENSIONS

Corrected and extended by R. J. Mathar, Feb 08 2008


STATUS

approved



