A considerable number of people get it wrong.
Can you solve it?
https://image.nostr.build/e74f4edc63593a21a8cdf55bcade0bd926be8ce801e675a056c735133272cf9a.jpg
Yn = n²+n
n=1, y=2 = 1²+1 = 2
n=2, y=6 = 2²+2 = 6
n=3=, y=12 = 3² + 3 = 12
n=4=, y=20 = 4² + 4 = 20
n=5=, y=30 = 5² + 5 = 30
n=6=, y=42 = 6² + 6 = 42
n=7=, y=56 = 7² + 7 = 56
n=8=, y=72 = 8² + 8 = 72
n=9=, y=90 = 9² + 9 = 90
n=1, y=2 = 1²+1 = 2
n=2, y=6 = 2²+2 = 6
n=3=, y=12 = 3² + 3 = 12
n=4=, y=20 = 4² + 4 = 20
n=5=, y=30 = 5² + 5 = 30
n=6=, y=42 = 6² + 6 = 42
n=7=, y=56 = 7² + 7 = 56
n=8=, y=72 = 8² + 8 = 72
n=9=, y=90 = 9² + 9 = 90