Semiprime's dividers concatenated

[Robert G. Wilson v]

Dear Eric,

	Easy, just build it from the concatenation of the primes.

Sort[ Flatten[ Table[ FromDigits[ Join[ IntegerDigits[ Prime[i]], IntegerDigits[ 
Prime[j]] ]], {i, 10}, {j, 10}] ]]

22, 23, 25, 27, 32, 33, 35, 37, 52, 53, 55, 57, 72, 73, 75, 77, 112, 113, 115, 
117, 132, 133, 135, 137, 172, 173, 175, 177, 192, 193, 195, 197, 211, 213, 217, 
219, 223, 229, 232, 233, 235, 237, 292, 293, 295, 297, 311, 313, 317, 319, 323, 
329, 511, 513, 517, 519, 523, 529, 711, 713, 717, 719, 723, 729, 1111, 1113, 1117, 
1119, 1123, 1129, 1311, 1313, 1317, 1319, 1323, 1329, 1711, 1713, 1717, 1719, 
1723, 1729, 1911, 1913, 1917, 1919, 1923, 1929, 2311, 2313, 2317, 2319, 2323, 
2329, 2911, 2913, 2917, 2919, 2923, 2929

Sincerely, Bob.


Eric Angelini wrote:

> Hello SeqFan,
> Here are the first semiprimes (A001358):
> 4,6,9,10,14,15,21,22,25,26,33,34,35,38,39,46...
> 
> I've just submitted to the OEIS quite a lot of
> sequences dealing with the concatenation of the
> dividers of the semiprimes, e.g.:
> First semiprime is 4; 4 is 2x2 --> 22
> Second semiprime is 6; 6 is 3x2 --> 32
>                          or 2x3 --> 23
> Third semiprime is 9; 9 is 3x3 --> 33
> Fourth semiprime is 10; 10 is 2x5 --> 25
>                            or 5x2 --> 52
> etc.
> 
> How would look an increasing sequence with
> all such "concatenated dividers", starting
> with the smallest one? I'm unable to build
> it by hand, fearing as always to forget one
> result behind...
> 
> Best,
> É.
> 
> 
>