OP solved it, closing

Thanks mate

Please don't post working solutions in discourse, it spoils the kata and if you do it anyway, please always "Mark as having spoiler content".

Your problem lies in i <- Range(0,n+1,5), linear solution will be too slow.

My Scala solution runs ~6.5s, so Scala version seems to be OK.

This is an early kata from 2013. A few years ago katas were ranked lower difficulties, than in the early years and the ranking system was changed. So you are definitely right.

There are two options. Reranking the old katas and as a consequence decrease the points of guys that took points for those kata. Option two is to accept this and grab some easy points.

I am not aware of plans for reranking. Perhaps a moderator is.

Cheers.