12 Days of Christmas
18th
Christmas Trees
17th
Diamonds
20th
Divisors
20th
Emirp Numbers
18th
Evil Numbers
14th
Fibonacci
34th
Fizz Buzz
21st
Happy Numbers
16th
Niven Numbers
28th
Odious Numbers
15th
Pangram Grep
51st
Pascal’s Triangle
23rd
Pernicious Numbers
31st
Prime Numbers
22nd
Quine
1st
π
13th
τ
11th