A140068 Triangle read by rows, n-th row = (n-1)-th power of the matrix X * [1,0,0,0,...] where X = an infinite lower triangular matrix with [1,2,1,2,1,2,...] in the main diagonal and [1,1,1,...] in the subdiagonal.
1, 1, 1, 1, 3, 1, 1, 7, 4, 1, 1, 15, 11, 6, 1, 1, 31, 26, 23, 7, 1, 1, 63, 57, 72, 30, 9, 1, 1, 127, 120, 201, 102, 48, 10, 1, 1, 255, 247, 522, 303, 198, 58, 12, 1, 1, 511, 502, 1291, 825, 699, 256, 82, 13, 1, 1, 1023, 1013, 3084, 2116, 2223, 955, 420, 95, 15, 1, 1, 2047, 2036
Offset: 1
Examples
First few rows of the triangle are: 1; 1, 1; 1, 3, 1; 1, 7, 4, 1; 1, 15, 11, 6, 1; 1, 31, 26, 23, 7, 1; 1, 63, 57, 72, 30, 9, 1; 1, 127, 120, 201, 102, 48, 10, 1; 1, 255, 247, 522, 303, 198, 58, 12, 1; ...
Crossrefs
Cf. A140069.
Formula
Triangle read by rows, n-th row = (n-1)-th power of the matrix X * [1,0,0,0,...] where X = an infinite lower triangular matrix with [1,2,1,2,1,2,...] in the main diagonal and [1,1,1,...] in the subdiagonal. Given the matrix X, perform X * [1,0,0,0,...] and then iterate: X * (result), etc. and record the result as each successive row of the triangle.
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