Lloyd Flounsbury established a Mesoamerican Long Count calendar correlation. To my knowledge he did not show how the Maya and others calculated the various synodic orbits, and the origin of the Tzolkin is still uncertain. Here I offer new insights. The universal mathematical tool of early times, in Egypt and Mesopotamia and Mesoamerica alike, have been number patterns and number sequences, the latter generating good values from bad and mediocre ones, and excellent values from mediocre and good ones. My claim is that the number 260 of the Tzolkin sprang from number sequences, and from the calculation of the circle based on the starting triple 5-12-13. These are new aspects, unbeknownst to Flansbury, and any other math historian, because they were discovered by me, and I make them public here. My opinion is that ancient calculation methods should be represented in an appropriate way, not with modern algebra, for example.