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A083029 Triangle read by rows: T(n,k), n >=1, 0 <= k <= C(n,k), = number of n X n symmetric positive semi-definite matrices with 2's on the main diagonal and 1's and 0's elsewhere and with k 1's above the diagonal. 9
1, 1, 1, 1, 3, 3, 1, 1, 6, 15, 20, 15, 6, 1, 1, 10, 45, 120, 210, 192, 200, 90, 45, 10, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,5
LINKS
EXAMPLE
1;
1,1;
1,3,3,1;
1,6,15,20,15,6,1;
...
CROSSREFS
Rows sums give A085658.
A038379(n) = Sum_{k=0..C(n, 2)} 2^k*T(n, k).
A084546 is an upper bound.
Sequence in context: A352472 A080858 A144228 * A084546 A288266 A174116
KEYWORD
nonn,tabf,more
AUTHOR
N. J. A. Sloane, Jul 13 2003
STATUS
approved

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Last modified March 19 01:57 EDT 2024. Contains 370952 sequences. (Running on oeis4.)