Errata and Addenda to Mathematical Constants

At this point, there are more additions than errors to report... 1.1. Pythagoras’ Constant. A geometric irrationality proof of √ 2 appears in [1] and a curious recursion is studied in [2]. More references on radical denestings include [3, 4, 5, 6]. 1.2. The Golden Mean. The cubic irrational χ = 1.8392867552... is mentioned elsewhere in the literature with regard to iterative functions [7, 8, 9] (the four-numbers game is a special case of what are known as Ducci sequences), geometric constructions [10, 11] and numerical analysis [12]. Another reference on infinite radical expressions is [13]. See [14] for an interesting optimality property of the logarithmic spiral. A mean-value analog C of Viswanath’s constant 1.13198824... (the latter applies for almost every random Fibonacci sequence) was discovered by Rittaud [15]: C = 1.2055694304... has minimal polynomial x + x − x − 2. The Fibonacci factorial constant c arises in [16] with regard to the asymptotics