For context, because I had to look it up: For BB(6), Σ(6) is known to be least 10 ↑↑ 15 for in Knuth's up-arrow notation. You can read this as 10^(10 ↑↑ 14) = 1

For context, because I had to look it up: For BB(6), Σ(6) is known to be least 10 ↑↑ 15 for in Knuth's up-arrow notation. You can read this as 10^(10 ↑↑ 14) = 10^(10^(10 ↑↑ 13)) and so on. It's much more than just a lot. Anyone know how many digits this is?