A146987
Sequences linked to this entry ?
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A146987: Triangle, read by rows, T(n, k) = binomial(n, k) for n < 2 and binomial(n, k) + 3^(n-1)*binomial(n-2, k -1) otherwise.
identification, match reversed triangle, match triangle
1 · 1, 1 · 1, 5, 1 · 1, 12, 12, 1 … Σ 1, 2, 7, 26, 124, 680, 3952, 23456, …