In combinatorial mathematics, any of a sequence of natural numbers that occur in various counting problems, often involving recursively defined objects; the nᵗʰ Catalan number is equal to (2n choose n) over (n+1).

plural of Catalan number

A conjectured Jewish language spoken by the Jews in Northeastern Spain, especially in Catalonia, Valencia and the Balearic Islands.

(mathematics) The number G=𝛽(2)=∑ₙ₌₀ ᪲((-1)ⁿ)/((2n+1)²)=1/(1²)-1/(3²)+1/(5²)-1/(7²)+1/(9²)-⋯, where β is the Dirichlet beta function, with a value of approximately 0.915965594177…

FC Barcelona

Alternative form of Judeo-Catalan

(geometry) A ruled surface whose rulings are all parallel to a fixed plane.

plural of Catalan surface

bloomery

plural of Catalan forge