Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/stm32/stm32f3/STM32F302/ADC1/SQR1#0x0
regular sequence register 1
L3
SQ1
SQ2
SQ3
SQ4
https://github.com/modm-io/cmsis-svd-stm32