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A104571
Triangle T(n,k) = A042948(n-k+1) read by rows, 0<=k<=n.
0
1, 4, 1, 5, 4, 1, 8, 5, 4, 1, 9, 8, 5, 4, 1, 12, 9, 8, 5, 4, 1, 13, 12, 9, 8, 5, 4, 1, 16, 13, 12, 9, 8, 5, 4, 1
OFFSET
0,2
FORMULA
The triangle is extracted from the product of lower triangular matrices (with the rest of the terms all zeros): G * R (or R * G); G = [1; 3, 1; 1, 3, 1; 3, 1, 3, 1;...]; R = [1; 1, 1; 1, 1, 1;...].
EXAMPLE
The first few rows are:
1;
4, 1;
5, 4, 1;
8, 5, 4, 1;
9, 8, 5, 4, 1;
...
CROSSREFS
Cf. A042948, A035608 (row sums), A104570, A104569, A074377.
Sequence in context: A214892 A030352 A212643 * A249057 A105721 A099310
KEYWORD
nonn,tabl,easy
AUTHOR
Gary W. Adamson, Mar 16 2005
STATUS
approved