12 Days of Christmas
71st
Abundant Numbers
50th
Abundant Numbers (Long)
39th
Arithmetic Numbers
34th
Christmas Trees
21st
Collatz
8th
Cubes
20th
Diamonds
28th
Fibonacci
223rd1st
Fizz Buzz
122nd
Foo Fizz Buzz Bar
18th
Fractions
30th
Happy Numbers
23rd
Happy Numbers (Long)
17th
Hilbert Curve
9th
Leap Years
40th
ln 2
11th
Look and Say
28th
Lucky Numbers
17th
Mandelbrot
16th
Niven Numbers
56th
Niven Numbers (Long)
30th
Pascal’s Triangle
34th
Quine
112th
Tongue-twisters
25th
Tower of Hanoi
42nd
Trinomial Triangle
9th
γ
10th
λ
18th
π
21st
τ
15th
φ
18th
√2
16th
𝑒
19th