12 Days of Christmas
11th
99 Bottles of Beer
9th
Abundant Numbers
33rd
Christmas Trees
6th
CSS Colors
7th
Diamonds
6th
Divisors
14th
Emirp Numbers
Fibonacci
52nd
Fizz Buzz
29th545th1,535th
Happy Numbers
38th
Intersection
5th
Leap Years
18th
Morse Decoder
3rd
Morse Encoder
4th
Niven Numbers
40th
Prime Numbers
40th
Seven Segment
5th
Sierpiński Triangle
13th
Tongue-twisters
19th
United States
7th