99 Bottles of Beer
18th
Abundant Numbers
27th
Christmas Trees
27th
Divisors
30th
Emirp Numbers
20th
Evil Numbers
41st
Fibonacci
69th
Fizz Buzz
146th
Leap Years
43rd
Morse Decoder
10th
Morse Encoder
9th
Niven Numbers
26th
Odious Numbers
35th
Ordinal Numbers
24th
Pascalβs Triangle
20th
Prime Numbers
25th
Roman to Arabic
24th
Seven Segment
18th
Ο
34th