Note: Each of the number except `28`, is a multiple of `3`

Note: Each of the numbers except 81 is a prime number

Note: Each of the numbers except 72, is a perfect square.

Note: Each of the numbers except 54 is a multiple of 5.

Note: The pattern is `1^2, 2^2, 3^2, 4^2, 5^2, 6^2, 7^2.` But instead of `5^2`, it is `20`, which is to be turned out.

Note: The pattern is `2^3, 3^3, 4^3, 5^3, 6^3, 7^3.` But `100` is not a perfect cube.

Note: The pattern is `1^2, 1^2, + 2^2, 1^2 + 2^2 + 3^2, 1^2 + 2^2 + 3^2 + 4^2,` `1^2 + 2^2 + 3^2 + 4^2 + 5^2, 1^2 + 2^2 + 3^2 + 4^2 + 5^2 + 6^2.` But 50 is not of this pattern.

Note: In Each number except `427`the middle digit is sum of the other two.

Note: In each number except `751`, the difference of third and first digit is the middle one.

Note: In each number except `383,` the product of first and third digits is the middle one.