let
    Source = List.Buffer(List.Transform(Table.ToColumns(Excel.CurrentWorkbook(){[Name="Таблица1"]}[Content]),List.RemoveNulls)),
    fn     = (n,k,optional i, optional j)=>
             let
                 i   = if i=null then 0 else i, 
                 j   = if j=null then 0 else j, 
                 tbl = Table.FromRecords(
                           List.TransformMany(
                               {i..n-k+j},
                               each Source{_},
                               (a,b)=>[x=b]&(if j<k-1 then [y=@fn(n,k,a+1,j+1)] else [])
                           )
                       ) 
             in 
                 if j<k-1 
                     then Table.ExpandTableColumn(
                         tbl,
                         "y",
                         {"x"}&List.Transform({j+1..k-2}, each "x"&Text.From(_+1)),
                         List.Transform({j+1..k-1}, each "x"&Text.From(_))
                     ) 
                 else tbl,
    ret    = fn(List.Count(Source),4)
in
    ret