PROG
(MAGMAMagma) T:= func< n, k | k eq n select 1 else k eq n-1 select 2 else 0 >;
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(MAGMAMagma) T:= func< n, k | k eq n select 1 else k eq n-1 select 2 else 0 >;
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Join[{1}, Flatten[Table[PadRight[{2, 1}, n, 0], {n, 3, 20}]]] (* Harvey P. Dale, Feb 28 2022 *)
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Triangle by columns: (1, 2, 0, 0, 0, ...) in every column.
Inverse = a triangle with (1, -2, 4, -8, 16, ...) in every column.
Triangle T(n,k), 0 <= k <= n, given by [2,-2,0,0,0,0,0,0,...] DELTA [1,0,0,0,0,0,0,0,...] where DELTA is the operator defined in A084938. - __Philippe Deléham_, Feb 08 2009
Triangle read by rows, T(n,k) = 1 if (n = k); , 2 if k = n-1, 0 otherwise.
By columns, (1, 2, 0, 0, 0, ...) in every column.
First few rows of the triangle =:
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