phi (golden ratio {1+{\sqrt {5}}}/{2}} = approx 1.618033988749894848204586834...
Chaitin constant (Chaitin omega number)[1] or halting probability is a real number that, informally speaking, represents the probability that a randomly constructed program will halt
Prouhet–Thue–Morse constant, named for Eugène Prouhet, Axel Thue, and Marston Morse, is the number—denoted by τ {\displaystyle \tau } \tau —whose binary expansion .01101001100101101001011001101001...