12 Days of Christmas
761st15th
99 Bottles of Beer
Abundant Numbers
17th
Christmas Trees
13th
Collatz
8th
Diamonds
465th
Divisors
17th
Fibonacci
3rd
Fizz Buzz
1,389th57th
Happy Numbers
538th
Intersection
10th
Kolakoski Sequence
8th
Leap Years
27th
Look and Say
230th5th
Niven Numbers (Long)
17th
Ordinal Numbers
11th
Pascal’s Triangle
19th
Prime Numbers
14th
Quine
1st
Roman to Arabic
14th
Seven Segment
9th
Sierpiński Triangle
13th
φ
10th
√2
8th