The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.



Please make a donation to keep the OEIS running. We are now in our 56th year. In the past year we added 10000 new sequences and reached almost 9000 citations (which often say "discovered thanks to the OEIS").
Other ways to donate

(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A329911 The number of rooted chains of reflexive matrices of order n. 0
1, 1, 6, 9366, 56183135190, 5355375592488768406230, 22807137588023760967484928392369803926, 9821625950779149908637519199878777711089567893389821437206 (list; graph; refs; listen; history; text; internal format)



Also, the number of n X n distinct rooted reflexive fuzzy matrices.

The number of chains in the power set of (n^2-n)-elements such that the first term of the chains is either an empty set or a set of (n^2-n)-elements.

The number of chains in the collection of all reflexive matrices of order n such that the first term of the chains is either identity matrix or unit matrix.


Table of n, a(n) for n=0..7.

S. R. Kannan and Rajesh Kumar Mohapatra, Counting the Number of Non-Equivalent Classes of Fuzzy Matrices Using Combinatorial Techniques, arXiv preprint arXiv:1909.13678 [math.GM], 2019.

V. Murali, Combinatorics of counting finite fuzzy subsets, Fuzzy Sets Syst., 157(17)(2006), 2403-2411.

M. Tărnăuceanu, The number of chains of subgroups of a finite elementary abelian p-group, arXiv preprint arXiv:1506.08298 [math.GR], 2015.


a(n) = A000629(n^2-n).


Cf. A000629, A038719, A007047, A328044, A330301, A330302, A330804, A331957.

Sequence in context: A158880 A137040 A172733 * A088021 A102979 A069942

Adjacent sequences:  A329908 A329909 A329910 * A329912 A329913 A329914




S. R. Kannan, Rajesh Kumar Mohapatra, Feb 29 2020



Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified November 24 06:34 EST 2020. Contains 338607 sequences. (Running on oeis4.)