

A080858


Triangle read by rows: T(n,k), n >=1, 0 <= k <= C(n,k), = number of n X n symmetric positive definite matrices with 2's on the main diagonal and 1's and 0's elsewhere and with w 1's above the diagonal.


8



1, 1, 1, 1, 3, 3, 1, 1, 6, 15, 20, 12, 6, 1, 1, 10, 45, 120, 190, 192, 140, 80, 30, 10, 1
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OFFSET

1,5


LINKS

Table of n, a(n) for n=1..25.
Index entries for sequences related to binary matrices


EXAMPLE

1; 1,1; 1,3,3,1; 1,6,15,20,12,6,1; ...


CROSSREFS

Rows sums give A085657. A085656(n) = Sum_{k=0..C(n, 2)} 2^k*T(n, k).
Sequence in context: A296186 A232967 A144163 * A144228 A083029 A084546
Adjacent sequences: A080855 A080856 A080857 * A080859 A080860 A080861


KEYWORD

nonn,tabf


AUTHOR

N. J. A. Sloane, Jul 13 2003


STATUS

approved



