12 Days of Christmas
49th
99 Bottles of Beer
Divisors
50th
Emirp Numbers
37th
Fibonacci
79th
Fizz Buzz
Foo Fizz Buzz Bar
Leap Years
Niven Numbers
47th
Ordinal Numbers
Pernicious Numbers
38th
Prime Numbers
54th
Rock-paper-scissors-Spock-lizard
165th
SierpiΕski Triangle
25th
Ξ»
17th
π
20th