12 Days of Christmas
44th
Abundant Numbers
116th
Diamonds
37th
Divisors
63rd
Fibonacci
130th
Gijswijt’s Sequence
176th
Hexdump
20th
Kolakoski Sequence
31st
Leap Years
37th
N Queens
10th
Niven Numbers
50th914th
Odious Numbers
58th
Partition Numbers
18th
Pernicious Numbers
60th
Prime Numbers
81st
Quine
256th
Recamán
28th
Rijndael S-box
10th
Tongue-twisters
24th406th
Tower of Hanoi
28th