What do you mean by oblong numbers?

Question

What is the 100th oblong number?

Answer 1

A pronic number, oblong number or heteromecic number, is a number which is the product of two consecutive integers, that is, n (n + 1).  

Answer 2

Any number that is the product of two consective integers. Oblong numbers are also known as pronic numbers. The first few of them are: 0, 2, 6, 12, 20, and 30.