A121609 Composite numbers that can be written as concatenation of two primes in decimal representation.

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

Offset

1,1

Comments

Subsequence of A066737.

Links

Jean-Marc Falcoz, Table of n, a(n) for n = 1..11140

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 A254753

Adjacent sequences: A121606 A121607 A121608 * A121610 A121611 A121612

Keyword

nonn,base

Author

Reinhard Zumkeller, Aug 10 2006

Status

approved