The gnomonic numbers are therefore equivalent to the odd numbers, and the first few are 1, 3, 5, 7, 9, 11, ... (OEIS A005408).
The generating function for the gnomonic numbers
is
Merzbach, U. C. and Boyer, C. B. A History of Mathematics, 3rd ed. New York: Wiley, p. 49, 1991.Sloane,
N. J. A. Sequence A005408/M2400
in "The On-Line Encyclopedia of Integer Sequences."
giving the area of the square gnomon obtained by removing a square
of side 
from a square of side 
,
