This reminds me of Knuth's conjecture. http://www.perlmonks.org/?node_id=443037 http://www.perlmonks.org/?node_id=443037 (Starting with 3, apply some combinatio

This reminds me of Knuth's conjecture. http://www.perlmonks.org/?node_id=443037 http://www.perlmonks.org/?node_id=443037 (Starting with 3, apply some combination of factorial, square root, and floor functions. Knuth conjectured all natural numbers are achievable this way.)