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A087558 a(n) = largest prime that is the concatenation of two numbers whose product is n. 1

%I

%S 11,0,31,41,0,61,71,0,19,101,0,43,131,0,151,0,0,181,191,0,211,211,0,

%T 241,251,0,271,281,0,103,311,0,331,0,0,0,137,0,313,401,0,421,431,0,59,

%U 461,0,163,491,0,317,521,0,541,0,0,571,229,0,601,0,0,631,641,0,661,167,0,691

%N a(n) = largest prime that is the concatenation of two numbers whose product is n.

%C a(3k+2) = 0. - _David Wasserman_, Jun 07 2005

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

%Y Cf. A087557.

%K base,nonn

%O 2,1

%A _Amarnath Murthy_, Sep 13 2003

%E More terms from _David Wasserman_, Jun 07 2005

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Last modified November 28 00:05 EST 2022. Contains 358406 sequences. (Running on oeis4.)