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A087558 a(n) = largest prime that is the concatenation of two numbers whose product is n. 1
11, 0, 31, 41, 0, 61, 71, 0, 19, 101, 0, 43, 131, 0, 151, 0, 0, 181, 191, 0, 211, 211, 0, 241, 251, 0, 271, 281, 0, 103, 311, 0, 331, 0, 0, 0, 137, 0, 313, 401, 0, 421, 431, 0, 59, 461, 0, 163, 491, 0, 317, 521, 0, 541, 0, 0, 571, 229, 0, 601, 0, 0, 631, 641, 0, 661, 167, 0, 691 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,1

COMMENTS

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

LINKS

Table of n, a(n) for n=2..70.

EXAMPLE

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

CROSSREFS

Cf. A087557.

Sequence in context: A274851 A075360 A256756 * A087555 A185682 A217752

Adjacent sequences:  A087555 A087556 A087557 * A087559 A087560 A087561

KEYWORD

base,nonn

AUTHOR

Amarnath Murthy, Sep 13 2003

EXTENSIONS

More terms from David Wasserman, Jun 07 2005

STATUS

approved

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Last modified October 4 03:29 EDT 2022. Contains 357237 sequences. (Running on oeis4.)