A051108 Numbers described with a single word in American English.
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 30, 40, 50, 60, 70, 80, 90, 100, 1000, 1000000, 1000000000, 1000000000000, 1000000000000000, 1000000000000000000, 1000000000000000000000
Offset: 0
Examples
"Nineteen" is one word, "twenty-one" is not.