12 Days of Christmas
29th
99 Bottles of Beer
15th
Arabic to Roman
42nd
Christmas Trees
10th
Cubes
7th
Diamonds
8th
Divisors
22nd
Emirp Numbers
19th
Evil Numbers
21st
Fibonacci
19th
Fizz Buzz
14th
Fractions
8th
Leap Years
12th
Odious Numbers
21st
Pernicious Numbers
13th
Quine
1st
694th
Sierpiński Triangle
11th
Spelling Numbers
43rd
Tongue-twisters
8th
λ
6th