A002019
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.
-
Triangle T(n,k) of arctangent numbers: expansion of arctan(x)^n/n!.
(match row sums)
-2, 0, 1 · 0, -8, 0, 1 · 24, 0, -20, 0, 1 … row sums -1, -7, 5, 145, -5, -6095, -5815, …