20%

Project Euler problems that are rated at 20% difficulty.

2019

• #87 - Prime power triples 15 Aug
• #70 - Totient permutation 14 Aug
• #61 - Cyclical figurate numbers 01 Jun

2018

• #82 - Path sum: three ways 27 May

2017

• #72 - Counting fractions 04 Aug
• #80 - Square root digital 21 Jun
• #89 - Roman numerals 19 Jun
• #64 - Odd period square roots 19 Jun