Triangular array

In mathematics and computing, a triangular array of numbers, polynomials, or the like, is a doubly indexed sequence in which each row is only as long as the row's own index.

Notable particular examples include these:

• Bell numbers ("Aitken's array" or the "Peirce triangle")
• Bell polynomials
• Boustrophedon transform
• Eulerian number
• Floyd's triangle
• Lozanić's triangle
• Narayana number
• Pascal's triangle
• Rencontres numbers
• Romberg's method
• Stirling numbers of the first kind
• Stirling numbers of the second kind