12 Days of Christmas
59th
99 Bottles of Beer
Divisors
53rd
Emirp Numbers
38th
Fibonacci
91st
Fizz Buzz
Foo Fizz Buzz Bar
Leap Years
Niven Numbers
54th
Ordinal Numbers
Pernicious Numbers
42nd
Prime Numbers
60th
Rock-paper-scissors-Spock-lizard
211th
Sierpiński Triangle
27th
λ
20th
𝑒
20th