12 Days of Christmas
507th
Abundant Numbers
184th
Arabic to Roman
219th
Christmas Trees
194th
Cubes
244th
Diamonds
139th
Divisors
1st
Emirp Numbers
262nd
Evil Numbers
42nd1st
Fibonacci
155th138th
Fizz Buzz
53rd
Happy Numbers
198th
Leap Years
201st
Morse Decoder
60th
Morse Encoder
72nd
Niven Numbers
43rd33rd
Odious Numbers
40th1st
Ordinal Numbers
4th
Pangram Grep
376th
Pascal’s Triangle
66th
Pernicious Numbers
370th
Prime Numbers
227th
Quine
63rd
Rock-paper-scissors-Spock-lizard
119th
Roman to Arabic
263rd
Rule 110
226th
Seven Segment
79th
Sierpiński Triangle
63rd
Spelling Numbers
170th
United States
122nd
φ
159th
√2
201st