Pentatonix, the five-member American a cappella group lost their vocalist Avi Kaplan in 2017 at the same time as their tribute to which group received over 250 million views?
Avi Kaplan: Avriel Benjamin "Avi" Kaplan is an American singer and songwriter, most well known as a past member of the a cappella group Pentatonix. Avi Kaplan:  He is known for his bass voice, and often acted as the vocal bass of Pentatonix.
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