Numbrix Loop

     An idea from Bosuonparedo on the Krazydad discord led me to create this proof-of-concept puzzle. Here are the rules :

    Draw a loop through the center of all cells. The loop travels orthogonally from cell to cell.

- The loop cannot branch or cross itself.

- Clues indicate the order in which the loop passes through the cells. Cells are indexed from 1 to N (N the number of cells in the grid).

- A ? can represent any digit, but no leading ? can be zero (e.g. ?6 cannot be 06). 

    Thanks to Kays, Menderbug and Rook for testing and feedback.

Penpa+ interface