12 Days of Christmas
91st
Abundant Numbers
171st
Arabic to Roman
15th
Christmas Trees
351st
CSS Colors
61st
Diamonds
113th
Divisors
1st
Emirp Numbers
50th
Evil Numbers
419th
Factorial Factorisation
54th
Fibonacci
197th
Fizz Buzz
68th
Gijswijt’s Sequence
31st
Happy Numbers
330th
ISBN
120th
Kaprekar Numbers
19th
Leap Years
184th
Levenshtein Distance
83rd
ln 2
118th
Morse Decoder
42nd
Morse Encoder
87th
Niven Numbers
90th
Odious Numbers
318th
Ordinal Numbers
107th
Pangram Grep
65th
Pascal’s Triangle
414th
Pernicious Numbers
209th
Prime Numbers
176th
Quine
83rd
Rijndael S-box
38th
Seven Segment
59th
Sierpiński Triangle
349th
Tongue-twisters
390th
United States
48th
π
60th