There are multiple bands called 5150: 1. Doujin Cirle known for arrangements in the power metal and symphonic death metal genres under specifically the シンフォニック東方 (Symphonic Touhou) series.
Their songs are composed generally by ryu-5150 (龍5150) who is a Japanese composer, musician, male vocalist and lyricist. He’s best known for making Touhou arrangements in the power metal and symphonic death metal genres.

Read more about 5150 on Last.fm.