12 Days of Christmas
50th
99 Bottles of Beer
37th
Abundant Numbers
60th
Arabic to Roman
27th
Christmas Trees
70th
CSS Colors
34th
Cubes
16th
Diamonds
20th
Divisors
31st
Emirp Numbers
42nd
Evil Numbers
85th
Fibonacci
1st
Fizz Buzz
56th
Happy Numbers
36th
Kolakoski Sequence
25th
Leap Years
45th
Look and Say
28th
Niven Numbers
48th
Odious Numbers
65th
Ordinal Numbers
35th
Pangram Grep
42nd
Pernicious Numbers
45th
Prime Numbers
38th
Quine
1st
RecamΓ‘n
33rd
Rule 110
21st
Seven Segment
38th
Spelling Numbers
22nd
Tongue-twisters
22nd
United States
31st
Vampire Numbers
36th
Van Eck Sequence
22nd
Ο
44th251st80th24th446th61st12th
Ο
24th120th
8th
Ο
24th
8th
β2
31st
9th
π
33rd
7th