A121574
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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A121574: Riordan array (1/(1-2*x), x*(1+x)/(1-2*x)).
(identification, match triangle)
1 · 2, 1 · 4, 5, 1 · 8, 16, 8, 1 … row sums 1, 3, 10, 33, 109, 360, 1189, 3927, …
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A121574 → reverse
(match reversed triangle)
1 · 1, 2 · 1, 5, 4 · 1, 8, 16, 8 … row sums 1, 3, 10, 33, 109, 360, 1189, 3927, …