What do we call the numbers that cannot be arranged into 2-row arrays?

odd numbers. I learned that from Roger. And the answer is the same as one several posts below.

Giberra

The numbers that cannot be arranged into 2-row arrays are called odd numbers. Odd numbers are numbers that are not divisible by 2 and leave a remainder of 1 when divided by 2. For example, the numbers 1, 3, 5, 7, 9, etc., are all odd numbers.

To determine if a number is odd or even, you can divide it by 2. If the remainder is 1, then the number is odd. If the remainder is 0, then the number is even.

Regarding your mention of "Giberra", I'm sorry, but I am not familiar with that term.