Eleven is written as two bars and a dot. It falls eleventh in a trecena of thirteen, near the close of the run, and the numbered day it forms with any given sign recurs once in each 260-day round like every other combination.
The regularity is worth restating because it is the whole basis of the count's use. There is no irregularity anywhere in the Tzolk'in, no intercalation, no correction and no leap day; it is a pure product of two cycles turning against each other. That is why it can be run continuously for millennia without accumulating error of any kind, and why the count kept by highland daykeepers today can be matched against Classic inscriptions.
Maya numerals are written with a dot for one and a bar for five, and the coefficient of a day is written in exactly that way in the inscriptions, set beside the day sign in its cartouche. The system is positional and includes a sign for zero, which is why the Long Count can be written as a string of places, but within the 260-day count no number above thirteen ever occurs and the notation stays simple.
Spectral, the modern name for this coefficient, is from Jose Arguelles's Dreamspell of 1987. The Dreamspell's own count does not track the traditional Tzolk'in day by day, since it handles leap days differently, so the two systems give different answers for the same date, which is a practical as well as a historical distinction.
Sources Maya Hieroglyphic Writing: An IntroductionJ. Eric S. Thompson with Dreamspell: The Journey of Timeship Earth 2013Jose Arguelles