for he is the kind of person
who is always thinking about the cost.
“Eat and drink,” he says to you,
but his heart is not with you.
Proverbs 23:7 NIV
- Catalan number (Wikipedia)
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.