[seqfan] Primes adding one of their digit to themselves

[Eric Angelini]

Hello SeqFans,
This seq might be of interest: the prime numbers N that
produce another prime number N* by adding to N one of N's
digits.

I find this by hand (errors and omissions almost certain),
read the first column :

N =
 29 (as 29+2=31, which is prime)
43 (as 43+4=47)
61 (as 61+6=67)
67 (as 67+6=73)
89 (as 89+8=97)
167 (as 167+6=173)
227 (as 227+2=229)
...
[BTW, I like this little "chain": 61-->67-->73 END. Are there
      longer such chains?]

We could also compute M, M being a prime that produces
another prime M* by adding to M the sum of M's digits.

We could also compute L, L being a prime that produces
another prime L* by adding to L the product of L's digits.

Best,
É.