Common Routines Archives - Page 2 of 3

By Mike Molony ⋅ April 9, 2009 ⋅ 2 comments

Evaluate the sum of all amicable pairs under 10,000.

By Mike Molony ⋅ April 9, 2009 ⋅ 11 comments

Find the sum of all the positive integers which cannot be written as the sum of two abundant numbers.

What is the millionth lexicographic permutation of the digits 0, 1, 2, 3, 4, 5, 6, 7, 8 and 9?

By Mike Molony ⋅ April 30, 2009 ⋅ 6 comments

Find the value of d < 1000 for which 1/d contains the longest recurring cycle.

By Mike Molony ⋅ April 8, 2009 ⋅ 3 comments

How many circular primes are there below one million?

By Mike Molony ⋅ March 29, 2009 ⋅ Post a comment

Find the sum of all numbers less than one million, which are palindromic in both base 10 and base 2.

By Mike Molony ⋅ April 23, 2009 ⋅ 10 comments

Find the sum of all eleven primes that are truncatable from both left to right and right to left.

By Mike Molony ⋅ March 26, 2009 ⋅ 3 comments

What is the largest 1 to 9 pandigital that can be formed by multiplying a fixed number by 1, 2, 3, … ?

By Mike Molony ⋅ April 28, 2009 ⋅ 6 comments

Find the sum of all pandigital numbers with an unusual sub-string divisibility property.

By Mike Molony ⋅ May 5, 2009 ⋅ 6 comments

Find the first four consecutive integers to have four distinct primes factors.

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