Proper noun
Ishango
A substation of Virunga National Park in the Democratic Republic of the Congo that is near the city of Goma.
Brooks, A. S. and Smith, C. C. (1987): "Ishango revisited: new age determinations and cultural interpretations", The African Archaeological Review, 5 : 65–78. Source: Internet
Common interpretations are that the Ishango bone shows either the earliest known demonstration of sequences of prime numbers citation or a six-month lunar calendar. Source: Internet