12 Days of Christmas
14th
Christmas Trees
15th
Diamonds
19th
Divisors
29th
Emirp Numbers
15th
Evil Numbers
15th
Fibonacci
48th
Fizz Buzz
61st
Happy Numbers
15th
Niven Numbers
36th
Odious Numbers
18th
Pangram Grep
48th
Pascal’s Triangle
28th
Pernicious Numbers
26th
Prime Numbers
29th
Quine
1st
π
14th
τ
12th