A001844
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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A023531 → (1/2)D²+2D+1 → x ↦ x/(x+1)
(match row sums)
1 · 2, 3 · 1, 6, 6 · 0, 3, 12, 10 … row sums 1, 5, 13, 25, 41, 61, 85, 113, …