12 Days of Christmas
55th
99 Bottles of Beer
Divisors
51st
Emirp Numbers
38th
Fibonacci
81st
Fizz Buzz
Foo Fizz Buzz Bar
Leap Years
Niven Numbers
48th
Ordinal Numbers
Pernicious Numbers
40th
Prime Numbers
56th
Rock-paper-scissors-Spock-lizard
170th
SierpiΕski Triangle
26th
Ξ»
18th
π
21st