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A068998 Numbers n such that the concatenation of the prime factors of n (in increasing order) is prime. 0
2, 3, 5, 6, 7, 8, 9, 11, 12, 13, 16, 17, 18, 19, 21, 22, 23, 24, 25, 27, 29, 31, 32, 33, 36, 37, 39, 41, 43, 44, 46, 47, 48, 49, 51, 53, 54 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..37.

EXAMPLE

The prime factors of 51 are 3 and 17 and their concatenation 317 is prime, so 51 belongs to the sequence.

CROSSREFS

Sequence in context: A039115 A285964 A198045 * A152854 A341763 A201144

Adjacent sequences:  A068995 A068996 A068997 * A068999 A069000 A069001

KEYWORD

base,easy,nonn

AUTHOR

Joseph L. Pe, Mar 16 2002

STATUS

approved

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Last modified May 7 19:17 EDT 2021. Contains 343652 sequences. (Running on oeis4.)