Arithmetic Numbers
8th
Collatz
8thDivisors
24th
Evil Numbers
1stEvil Numbers (Long)
1stLeap Years
16th
Leyland Numbers
17th
Look and Say
5thNiven Numbers
20thNiven Numbers (Long)
17thOdious Numbers
1stOdious Numbers (Long)
1stPernicious Numbers
23rdPernicious Numbers (Long)
12thPrime Numbers
1st
1stPrime Numbers (Long)
1st
Smith Numbers
15th
United States
3rd
π
69th