# [Japt], <s>31</s> 18 bytes

-13 bytes thanks to [@ETHproductions](https://codegolf.stackexchange.com/users/42545/ethproductions)

This approach doesn't work well using Japt. [Justin's solution](https://codegolf.stackexchange.com/a/138194/61613) is much better. 

    [U*Ål U¬£tYÃUå+]xx

##Explanation:
    [U*Ål U¬£tYÃUå+]xx
    [              ]    // Create a new array
     U*Ål               // Push: Input * Input.slice(1).length()
                        // Push:
          U¬            //   Input, split into chars
            £tY         //   Map; At each char: .substr(Index)
                Uå+     // Push: Cumulative reduce Input; with addition
                    xx  // Sum all the items, twice

[Try it online!][TIO-j66l38wo]

[Japt]: https://github.com/ETHproductions/japt
[TIO-j66l38wo]: https://tio.run/##y0osKPn/PzpU63BrjkLooTWHFpdEHm4OPbxUO7ai4v9/JUMjYxNTM3MlAA "Japt – Try It Online"