Note 1039 — Chapter XI · THE MYSTICAL MEANINGS IN THE PROPORTIONS OF NUMBERS, GEOMETRICAL RATIOS, AND MUSIC.
William Wilson translation
“Triangular numbers are those which can be disposed in a triangle, as 3 , 6 , etc., being represented by the formula (Liddel and Scott’s Lexicon). Each side of the triangle of course contains an equal number of units, the sum of which amounts to the number.
