Figurate numbers >>
Constructed in this way, the successive diagonal rows, commencing with the first, give the figurate numbers of the first, second, third,.
The (r+1)th figurate number of the nth order, i.e.
FIGURATE NUMBERS, in mathematics.
Or rth order of figurate numbers.
It appears that Pascal contemplated publishing a treatise De aleae geometria; but all that actually appeared was a fragment on the arithmetical triangle (Traite du triangle arithmetique, " Properties of the Figurate Numbers"), printed in 1654, but not published till 1665, after his death.