# What do these numbers have in common?

What do these numbers have in common that no other numbers between 1 and 100 share? 4, 6, 12, 30, 33, 36, 40, 45, 50, 54, 56, 60, 70, 81, 88, 90, 100

-
They are all on the list of numbers in your post. –  Zev Chonoles Oct 13 '11 at 23:38
Good one! Anything else? –  Josie Oct 13 '11 at 23:40
oeis.org/A092320 –  Chris Taylor Oct 13 '11 at 23:40
This? –  Ｊ. Ｍ. Oct 13 '11 at 23:41
"American English" is to help decide whether the next term is "one hundred and eight" or "one hundred twelve". –  Henry Oct 14 '11 at 0:10

Each of the numbers $n$ in your list is divisible by the number of digits in the English word for $n$.

For example:

• the English word for '4' is "four" which has 4 letters, and 4 / 4 = 1
• the English word for '6 is "six" which has 3 letters, and 6 / 3 = 2
• the English word for '12' is "twelve" which has 6 letters, and 12 / 6 = 2
• the English word for '30' is "thirty" which has 6 letters, and 30 / 6 = 5
• the English word for '33' is "thirty-three' which has 11 letters, and 33 / 11 = 3

Do you see the pattern now?

-
Yes! Thanks so much. –  Josie Oct 13 '11 at 23:51