SeqTxns with 9 sequences, 12 transactions, 16 items, and 46 non-zero elements
 Sequence │ Transaction │ Items
──────────┼─────────────┼──────────────────────
        1 │ 1           │ milk, eggs, bread
          │ 2           │ eggs, ham, cheese,…
        2 │ 1           │ milk, eggs, butter,…
        ⋮ │ ⋮           │ ⋮
        7 │ 1           │ milk, eggs, sugar
        8 │ 1           │ milk, beer,…
        9 │ 1           │ eggs, ham, cheese,…
