12 Days of Christmas
10th
99 Bottles of Beer
14th
Arabic to Roman
7th
Christmas Trees
13th
Divisors
36th
Emirp Numbers
13th
Evil Numbers
21st
Fibonacci
61st
Fizz Buzz
85th
Happy Numbers
10th
Niven Numbers
49th
Odious Numbers
21st
Pascal’s Triangle
18th
Pernicious Numbers
23rd
Prime Numbers
41st
Quine
1st
Roman to Arabic
12th
Seven Segment
11th
Sierpiński Triangle
10th
π
11th