

A330032


The number of chains of strictly rooted upper triangular or lower triangular matrices of order n.


0



1, 2, 26, 9366, 204495126, 460566381955706, 12595124129900132067036747870669270, 288398561903310939256721956218813835167026180310, 2510964964470962082968627390938311899485883615067802615950711482
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OFFSET

0,2


COMMENTS

Also, the number of chains in the power set of (n^2n)/2elements such that the first term of the chains is either an empty set or a set of (n^2n)/2elements.
The number of rooted chains of 2element subsets of {0,1, 2, ..., n} that contain no consecutive integers.
The number of distinct rooted reflexive symmetric fuzzy matrices of order n.
The number of chains in the set consisting of all n X n reflexive symmetric matrices such that the first term of the chains is either reflexive symmetric matrix or unit matrix.


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FORMULA



CROSSREFS



KEYWORD

nonn


AUTHOR



STATUS

approved



