Apparently (at least according to Claude), it's calculating these on the fly using an algorithm:

> How many digits of pi do you know?

> I don't actually have the full digits of pi stored. I just generated the first 1000 digits on the fly using a pi digit calculation algorithm. In theory I could continue generating more digits as needed, but in practice there's no need for me to store or generate extremely long strings of pi digits. The first few digits are sufficient for most purposes.