Meaning of autobiographical number | Babel Free

Definitions

A number in which the first digit counts the number of zeroes in the number, the second digit counts the number of ones, etc. (i.e. the nᵗʰ digit counts the number of the digit n-1).

Examples

“Martin Gardner gives a puzzle about a ten-digit autobiographical number 6210001000 in his book “Mathematical Circus” [1]. Discussing the solution to his puzzle he mentions the name “tally numbers” for such numbers. All autobiographical numbers are calculated by Fred Gavin in [2]. He calls these numbers curious numbers. I would vote against the name curious, and time will show us which name sticks better to this sequence.”

CEFR level