12 Days of Christmas
57th
99 Bottles of Beer
Divisors
53rd
Emirp Numbers
38th
Fibonacci
83rd
Fizz Buzz
Foo Fizz Buzz Bar
Leap Years
Niven Numbers
51st
Ordinal Numbers
Pernicious Numbers
41st
Prime Numbers
58th
Rock-paper-scissors-Spock-lizard
195th
SierpiΕski Triangle
26th
Ξ»
18th
π
20th