cp's OEIS Frontend

For the construction of this sequence we use the same the rules of A187210 (the Q-toothpick sequence) except that for the even-indexed generations here we use Q-toothpicks of radius 2, not 1.

The result is that the structure looks like an arrangement of ovals.

On the infinite square grid at stage 0 we start with no Q-toothpicks, so a(0) = 0.

For n >= 1, a(n) is the ratio between the total length of the lines of the structure after n-th stages and the length of a single Q-toothpick of radius 1.

A187210(n) gives the total number of Q-toothpicks in the structure after n-th stages.

A187211(n) gives the number of Q-toothpicks added at n-th stage.

Note that since the radius of the Q-toothpicks can be two distincts numbers so we can write an infinite number of sequences from cellular automata of this kind.