Answer 1

"A neon number is a number where the sum of digits of square of the number is equal to the number" (CodeQuiz, 2015).

Example:
1
The square of 1 is 1.
The sum of those digits is 1.
1 = 1, therefore neon.

9
The square of 9 is 81.
The sum of those digits (8 + 1) is 9.
9 = 9, therefore neon.