What are the numbers in the question marks?

0, 1, 2, ?, 5, 6, 8, ?, 40, 46, 60, ?, 84


I have a theory that

These are numbers that, spelled out in English, have no duplicate letters.

This way

The first question mark would be FOUR (since THREE has 2 E's), the second one - TEN (NINE, ELEVEN, TWELVE, *TEEN, TWENTY * and THIRTY * are out).

But I'm confused by the 3rd question mark, as

There are multiple numbers between 60 and 84 that can be spelled without duplicate letters: SIXTY ONE, SIXTY FOUR and EIGHTY itself. I'm not sure how to pick just one of them...

  • 1
    $\begingroup$ Yeah, I found this pattern after searching it up on the OEIS, also with both 61 and 64 being between 60 and 84. I would take a random guess that the question asker accidentally wrote SIXTY as SIXETY, and 64 would be the correct answer, but that could be wrong. $\endgroup$ Mar 8 at 5:24

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.