12 Days of Christmas
40th
99 Bottles of Beer
32nd
Abundant Numbers
58th
Arabic to Roman
25th
Christmas Trees
66th
CSS Colors
30th
Cubes
13th
Diamonds
18th
Divisors
30th
Emirp Numbers
36th
Evil Numbers
71st
Fibonacci
1st
Fizz Buzz
48th
Happy Numbers
32nd
Kolakoski Sequence
22nd
Leap Years
42nd
Look and Say
27th
Niven Numbers
45th
Odious Numbers
56th
Ordinal Numbers
30th
Pangram Grep
38th
Pernicious Numbers
40th
Prime Numbers
34th
Quine
1st
RecamΓ‘n
29th
Rule 110
19th
Seven Segment
36th
Spelling Numbers
18th
Tongue-twisters
18th
United States
28th
Vampire Numbers
30th
Van Eck Sequence
21st
Ο
40th
224th
69th
18th
374th
54th
11th
Ο
20th
106th
7th
Ο
21st
7th
β2
29th
8th
π
31st
6th