The story
Punningly on cube (mathematical sense) and Cuban, though there is no meaningful connection with the country of Cuba.
Etymology from Wiktionary, CC BY-SA 4.0.
cuban prime
Today it means: A prime number that is a solution to one of two specific equations involving third powers of x and y. The two equations are p=(x³-y³)/(x-y),x=y+1,y>0 and p=(x³-y³)/(x-y),x=y+2,y>0. Full definition →