Cycling Digit Patterns' The College Mathematics Journal, Vol. 27, No. 2. (Mar., 1996), pp. 109–115. Leslie, John. "The Philosophy of Arithmetic: Exhibiting a Progressive View of the Theory and Practice of ....", Longman, Hurst, Rees, Orme, and Brown, 1820, Wells, David; "The Penguin Dictionary of Curious and Interesting Numbers", Penguin Press. External links Youtube: "Cyclic Numbers - Numberphile" Number theory Permutations