[seqfan] Interlude

[Hans Havermann]

A wee bit of summer-hours fun for our intrepid programmers:

The smallest decimal-digits probable prime composed of the  
concatenation of 290 distinct decimal-digit "component" primes is (I  
think) the 963-digit number 10091011013...97797991983. Shown at  
indices 1-3 are {1009, 101, 1013}, and at indices 287-290, {977, 97,  
991, 983}. What is the index of the number's largest component prime?