Thank you very much graff ! Your example is very informative and self-explanatory. As for the data itself, it exists in the database in the form I showed, I am free to build the chains of numbers, but they does not exist in the raw form.

Update: I benchmarked your solution with this of mine ( Re^2: Looking for the first item in the chain ) - your code is 48% faster!

In reply to Re^2: Looking for the first item in the chain by vagabonding electron
in thread Looking for the first item in the chain by vagabonding electron

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