A154227
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.
-
A154227: Triangle T(n, k) = T(n-1, k) + T(n-1, k-1) + ((n+1)*(n+2)/2)*T(n-2, k-1), read by rows.
(identification, match reversed triangle, match triangle)
1 · 1, 1 · 1, 8, 1 · 1, 19, 19, 1 … row sums 1, 2, 10, 40, 230, 1300, 9040, 64880, …