# [Jelly], 16 bytes J:g¥’}U×ḷb§¥ƬṪS% [Try it online!][TIO-lzn1shx9] [Jelly]: https://github.com/DennisMitchell/jelly [TIO-lzn1shx9]: https://tio.run/##y0rNyan8/9/LKv3Q0kcNM2tDD09/uGN70qHlh5YeW/Nw56pg1f@Hl@trRv7/Hx0dbaijYKKjYBirY2gUq8MVHW2uY6hjpGOsY6JjqmOmY65joWOpY2igYwlXAORA5eFCyCKGEEUQU4kw2NAAu8mGSCYbw0ViAQ "Jelly – Try It Online" A less naive computation of the digital roots comes out a bit longer by having to special-case 0. Inverted output: truthy (nonzero) if the checksum fails. ``` J 1-indices from the start : divided by g¥ their GCDs with ’} B - 1 U reversed ×ḷ times each N. ƬṪ Loop while unique: b ¥ Convert each to base B § and sum each. S Sum % mod B. ```