- In combinatorial mathematics, the Catalan numbers are a sequence of natural numbers that occur in various counting problems, often involving recursively defined objects. They are named after the French-Belgian mathematician Eugène Charles Catalan.
For in sixe dayes the Lorde made both heauen and erth and the see and all that in them is and rested the seuenth daye: wherfore the Lorde blessed the Sabbath daye and halowed it.
Exodus 20:11 TYN