A340556
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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A340556: E2(n, k), the second-order Eulerian numbers with E2(0, k) = δ_{0, k}. Triangle read by rows, E2(n, k) for 0 <= k <= n.
(identification, match triangle)
A163936 → reverse1 · 0, 1 · 0, 1, 2 · 0, 1, 8, 6 … row sums 1, 1, 3, 15, 105, 945, 10395, 135135, …