[This is a repost from our archives with new notes at the top (original post here): Sometimes it is hard to understand when a clue in an Outside Sudoku is very necessary, somewhat necessary, or superfluous. With a few different themes overlapping in this puzzle (including Fibonacci numbers, multiples of 2, and cubes) the important thing will be to make out how to “use” each clue even if that does not mean putting in sure placements yet.]

PDF

or solve online (using our beta test of Penpa-Edit tools; use tab to alternate between Sudoku entry modes and a shading mode to mark off clues.)

Theme: A series of series (and a constant and a square) — The seemingly random numbers outside the grid actually have some rhyme and reason.

Rules: Standard Outside Sudoku rules.

Estimated Difficulty*: 3 stars

Time Standards (highlight to view): Grandmaster = 4:00, Master = 7:15, Expert = 14:30

Solution: PDF

Note: Follow this link for more Outside Sudoku puzzles. More Outside Sudoku puzzles can be found in Masterpiece Sudoku Mix 4.