12 Days of Christmas
15th
Christmas Trees
15th
Diamonds
20th
Divisors
33rd
Emirp Numbers
17th
Evil Numbers
16th
Fibonacci
65th
Fizz Buzz
66th
Happy Numbers
15th
Niven Numbers
40th
Odious Numbers
19th
Pangram Grep
49th
Pascal’s Triangle
32nd
Pernicious Numbers
31st
Prime Numbers
33rd
Quine
1st
π
15th
τ
13th