Fractional part of 69^(1/3) = 1/10 + 1/639 + 1/1015770 + ... Generated with Perl's Math::BigFloat module. Number of digits in terms is as follows: 2, 3, 7, 13, 26, 53, 105, 212, 423, ...
EXAMPLE
Cube root of 69 = 4.1015659297023475218471849821418748076501058467862...