12 Days of Christmas
26th
99 Bottles of Beer
35th
Abundant Numbers
22nd
Arabic to Roman
26th
Christmas Trees
11th
Divisors
21st
Emirp Numbers
25th
Evil Numbers
53rd
Fibonacci
21st
Fizz Buzz
45th
Foo Fizz Buzz Bar
19th
Happy Numbers
51st
Leap Years
27th
Niven Numbers
34th
Odious Numbers
51st
Ordinal Numbers
21st
Pangram Grep
9th
Pascal’s Triangle
35th
Pernicious Numbers
41st
Prime Numbers
42nd
Roman to Arabic
13th
Seven Segment
18th
Spelling Numbers
United States
24th
λ
15th
π
27th
τ
20th
φ
33rd
√2
39th
𝑒
27th