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A121609 Composite numbers that can be written as concatenation of two primes in decimal representation. 6
22, 25, 27, 32, 33, 35, 52, 55, 57, 72, 75, 77, 112, 115, 117, 132, 133, 135, 172, 175, 177, 192, 195, 213, 217, 219, 231, 232, 235, 237, 243, 247, 253, 259, 261, 267, 273, 279, 289, 292, 295, 297, 312, 315, 319, 323, 329, 341, 343, 361, 371, 372, 375, 377 (list; graph; refs; listen; history; internal format)
OFFSET

1,1

COMMENTS

Subsequence of A066737.

EXAMPLE

A002808(249) = 315 = 31*10+5 = A000040(11)*10+A000040(3),

therefore 315 is a term: a(44) = 315;

A002808(252) = 319 = 3*100+19 = A000040(2)*100+A000040(8),

therefore 319 is a term: a(45) = 319.

CROSSREFS

Cf. A121610, A105184, A121608.

Sequence in context: A034304 A167459 A066737 * A092631 A061371 A070809

Adjacent sequences:  A121606 A121607 A121608 * A121610 A121611 A121612

KEYWORD

nonn,base

AUTHOR

Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Aug 10 2006

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Last modified February 17 02:08 EST 2012. Contains 205978 sequences.