Investigating minimal repunits that divide by n.
Finding square sums that are palindromic.
Finding composite values, n, for which nā1 is divisible by the length of the smallest repunits that divide it.
Determining the first forty prime factors of a very large repunit.
Investigating which primes will never divide a repunit containing 10**n digits.
Count how many numbers below a googol (10**100) are not “bouncy”
Investigating the density of “bouncy” numbers.
Recover your combination to your new or old Master Lock combination lock in a few easy steps.
Determining the number of solutions of the equation x2 ā y2 ā z2 = n.
Find Fibonacci numbers for which the first and last nine digits are pandigital.