12 Days of Christmas
9th
99 Bottles of Beer
14th
Arabic to Roman
7th
Christmas Trees
13th
Divisors
35th
Emirp Numbers
12th
Evil Numbers
21st
Fibonacci
58th
Fizz Buzz
84th
Happy Numbers
10th
Niven Numbers
47th
Odious Numbers
21st
Pascal’s Triangle
17th
Pernicious Numbers
23rd
Prime Numbers
39th
Quine
1st
Roman to Arabic
11th
Seven Segment
11th
Sierpiński Triangle
9th
π
11th