12 Days of Christmas
18th
Christmas Trees
17th
Diamonds
19th
Divisors
19th
Emirp Numbers
17th
Evil Numbers
13th
Fibonacci
32nd
Fizz Buzz
19th
Happy Numbers
15th
Niven Numbers
27th
Odious Numbers
15th
Pangram Grep
51st
Pascal’s Triangle
21st
Pernicious Numbers
30th
Prime Numbers
20th
Quine
1st
π
14th
τ
12th