[seqfan] Re: Are these sequences in the OEIS?

[David Wilson]

On 6/3/2012 1:47 PM, Hans Havermann wrote:
> "23 It is the smallest number that is the concatenation of two primes 
> 2 and 3. 237 is the smallest number that can be separated into two 
> primes in two different ways: 2-37, 23-7..." 

Depending on your domain (nonnegative or positive integers), you might 
want a(0) = 0 or 1, probably best to leave it out. For n = 1 on, I get

22, 237, 2337, 29397, 739397, 23932917...

If you want to exclude repeated parts, a(1) = 23.