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I've noticed that some prime number are composed entirely of other prime numbers

for example -- some have parents on the left hand side (all the numbers below are prime):

59393339
5939333
593933
59393
5939
59
5

Others for example -- some have parents on the right hand side (all the numbers below are prime):

633396997
 33396997
  3396997
   396997
    96997
     6997
      997
       97
        7

Others have parents on both side, for example:

739397 on the right hand side
 39397
  9397
   397
    97
     7

739397 on the left hand side
73939
7393
739
73
7

I'd like to know what these type of Prime numbers are called?

Thanks.

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They're called truncatable primes.

For a list of them on OEIS, see A024785, A020994, A055521

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