Concerns about this recursive algorithm

[ForceBru]

More people looping over integers instead of ranges:

• https://discourse.julialang.org/t/i-in-3-is-valid-and-continues-to-cost-me-some-debug-time
• https://discourse.julialang.org/t/rant-i-hate-that-its-possible-to-iterate-over-an-integer