Abundant Numbers
43rd
Christmas Trees
31st
Day of Week
1st
Diamonds
14th
Divisors
1st
Emirp Numbers
10th
Fibonacci
1st
Fizz Buzz
12th
Leap Years
30th
ln 2
7th
Look and Say
18th
Ordinal Numbers
11th
Pangram Grep
18th
Pascal’s Triangle
17th
Pernicious Numbers
31st
Prime Numbers
23rd
Quine
1st
Recamán
10th