[seqfan] Spiral generated from A001045 a(n) = a(n-1) + 2*a(n-2)

[Dale Gerdemann]

Hello Seqfans,

In my YouTube video https://www.youtube.com/watch?v=9fAHnqeAFlQ some
unusual (for me at least) spirals appeared:
https://www.flickr.com/photos/104464263@N05/15460960064/

Is this perhaps a well known, well studied spiral?

What I notice about the spiral is:

1. The red and black intertwined spirals appear to be similar.

2. If you extend the hypotenuse of any of the inner turquoise triangles so
that it crosses the red territory, then this line after it emerges on the
other side, appears to bisect the right angle of an outer turquoise
triangle.


Thanks for the help,

Dale Gerdemann