A140880
identification: the entry's rule defines the sequence for every index; tail: the sequence is the entry's tail after some prefix rows; match_*: finite agreement only.
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A007318 → D → D
(match reversed triangle, match triangle)
2 · 6, 6 · 12, 24, 12 · 20, 60, 60, 20 … row sums 0, 0, 2, 12, 48, 160, 480, 1344, …