13th root 13th root Extracting the 13th root of a number is a famous category for the mental calculation world records. The challenge consists of being given a large number (possibly over 100 digits) and asked to return the number that, when taken to the 13th power, equals the given number. For example, the 13th root of 8,192 is 2 and the 13th root of 96,889,010,407 is 7. Extracting the 13th root has certain properties. One is that the 13th root of a number is much smaller: a 13th root will have approximately 1/13th the number of digits. Thus, the 13th root
Primitive root modulo n column is a primitive root modulo that number. The columns are labelled with the primes less than 100. The entry in row "p", column "q" is the index of "q" modulo "p" for the given root. For example, in row 11, 2 is given as the primitive root, and in column 5 the entry is 4. This means that 2 = 16 ≡ 5 (mod 11). For the index of a composite number, add the indices of its prime factors.For example, in row 11, the index of 6 is the sum of the indices for 2 and 3: . The