The (double) Primorial sieve  &  Prime spirals E-mail

The counterclockwise  Q1 spiral  with startvalue 0  is based on the counterclockwise  Ulam spiral  with  startvalue 0. 
The natural numbers in the  Q1 spiral  are placed only in the first quadrant of the Cartesian coordinate system.

Just like with the  Ulam spiral  the  Q1 spiral  has several   families of functions.
However the   families of functions  are less distinct (see below).


Miscellaneous: Q1 spiral  in a Cartesian coordinate system