power query- generate a list for each record using "offset down" logic

First add an Index column (with a starting index of 0).

Then add a custom column with the formula:

= if [number]=0 then null 
    else List.Range(#"Added Index"[text],[Index]+1,[number])

Finally, remove that Index column

The M Code to reproduce this, which you can paste into a blank query:

let

//the data
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("VY5LCoAwDESvIlm7EPU2xUWUoMX0Q2wt3t6iWHX5ZjKTUQrQeyaooYGhVuAJpXqJo8nQXWDQzi5Te1va0j+aMJAYYmeLtAXBNJLIUXJzxB3LwciRHr+/FCf5zVvKZD59q076O3VaCqEXPblw83AC", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [text = _t, number = _t]),

//set the data types
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"text", type text}, {"number", Int64.Type}}),

    #"Added Index" = Table.AddIndexColumn(#"Changed Type", "Index", 0, 1, Int64.Type),

//add custom column
    #"Added Custom" = Table.AddColumn(#"Added Index", "List", 
        each if [number]=0 then null 
                else List.Range(#"Added Index"[text],[Index]+1,[number])),
    #"Removed Columns" = Table.RemoveColumns(#"Added Custom",{"Index"})
in
    #"Removed Columns"