English Kelly–Hopkinsville encounter Cited by user 69.158.189.225 on 14 Jul 2023 The Kelly–Hopkinsville encounter (also known as the Hopkinsville Goblins Case or Kelly Green Men Case) was a claimed close encounter with extraterrestrial beings in 1955…
English Triangular number Cited by user David Eppstein on 04 Jan 2021 A triangular number or triangle number counts objects arranged in an equilateral triangle.