A118394
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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A118394: Triangle T(n,k) = n!/(k!*(n-3*k)!), for n >= 3*k >= 0, read by rows.
(identification, match triangle)
1 · 1 · 1 · 1, 6 … row sums 1, 1, 1, 7, 25, 61, 481, 2731, …