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A046451 Concatenation of the 2 prime factors of composite a(n) is a palindrome. 0
4, 9, 25, 39, 49, 69, 119, 121, 129, 159, 219, 249, 259, 329, 339, 403, 469, 669, 679, 1207, 1329, 1589, 1703, 2319, 2321, 2359, 2649, 2701, 3039, 3421, 3503, 3629, 3639, 3899, 4303, 4607, 4839, 5603, 5739, 6209, 6401, 6979, 7269, 7663, 7819, 8203, 8519 (list; graph; refs; listen; history; internal format)
OFFSET

1,1

EXAMPLE

E.g. 3899 = 7 * 557 -> 7557 is palindromic.

CROSSREFS

Cf. A046447.

Sequence in context: A046659 A063760 A130448 * A158142 A158143 A082200

Adjacent sequences:  A046448 A046449 A046450 * A046452 A046453 A046454

KEYWORD

nonn,base

AUTHOR

Patrick De Geest (pdg(AT)worldofnumbers.com), Jul 15 1998.

EXTENSIONS

Edited by Charles R Greathouse IV (charles.greathouse(AT)case.edu), Apr 28 2010

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Last modified February 16 12:41 EST 2012. Contains 205909 sequences.