Normal sudoku rules apply.
Thermo rules apply. Digits must increase from the bulb of a thermometer.
The grey square is an even digit.
Normal killer sudoku rules apply. Digits must sum up to the number in the top left corner. Numbers may not repeat in a given cage.
X-sum rules apply. Numbers outside the grid represent the sum of the first X cells in the row/column from that direction, where X is the first digit in the row/column.
It is recommended that you uncheck the setting in F-puzzles to highlight conflicts. It will not recognize the X-sum clues because they have been entered as sandwich clues.
Solution code: Row 3 followed by row 7
on 13. January 2021, 09:21 by Narayana
Here is an improved link that solves the issue with the 20 and 21 in the outside.
https://f-puzzles.com/?id=yxzulbyj
on 30. December 2020, 05:50 by brandon_bot
One alternative to entering them as sandwich clues is to use Cosmetic Tools -> Text -> Place Mode: Outside.
on 30. December 2020, 02:01 by Konzert
Clarified rules and revised rating
on 30. December 2020, 01:52 by Greg
Nice but probably not 3 star difficulty compared to some of the other 3 stars on here.
@CountSudokula
Yes
on 30. December 2020, 00:30 by CountSudokula
And the grey square is an even number? Just making sure.