Pronic

A kind of number

About Pronic

A pronic number (or oblong number) is the product of two consecutive integers: n(n+1). So 2, 6, 12, 20, 30, … They represent rectangles with sides n and n+1.

Key features

  • Equal to twice a triangular number: 2×T_n = n(n+1).
  • The first few are 2, 6, 12, 20, 30, 42, 56, 72, 90, 110.

Examples:

2, 6, 12, 20, 30, 42, 56, 72, 90

Further reading