12 Days of Christmas
45th
99 Bottles of Beer
34th
Abundant Numbers
58th
Arabic to Roman
25th
Christmas Trees
66th
CSS Colors
30th
Cubes
14th
Diamonds
18th
Divisors
30th
Emirp Numbers
37th
Evil Numbers
71st
Fibonacci
1st
Fizz Buzz
48th
Happy Numbers
33rd
Kolakoski Sequence
22nd
Leap Years
43rd
Look and Say
27th
Niven Numbers
45th
Odious Numbers
56th
Ordinal Numbers
30th
Pangram Grep
38th
Pernicious Numbers
40th
Prime Numbers
35th
Quine
1st
RecamΓ‘n
29th
Rule 110
19th
Seven Segment
36th
Spelling Numbers
18th
Tongue-twisters
19th
United States
29th
Vampire Numbers
31st
Van Eck Sequence
21st
Ο
40th
231st
71st
20th
384th
55th
11th
Ο
21st
108th
7th
Ο
21st
7th
β2
29th
8th
π
31st
6th