login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A189507 Triangle read by rows: T(n,k) (n >= 0, 1 <= k <= n+1) are the signed Hultman numbers. 7

%I

%S 1,1,1,4,3,1,20,21,6,1,148,160,65,10,1,1348,1620,701,155,15,1,15104,

%T 19068,9324,2247,315,21,1,198144,264420,138016,38029,5908,574,28,1,

%U 2998656,4166880,2325740,692088,124029,13524,966,36,1,51290496,74011488,43448940,13945700,2723469,344961,27930,1530,45,1,979732224,1459381440,897020784,305142068,64711856,8996295,850905,53262,2310,55

%N Triangle read by rows: T(n,k) (n >= 0, 1 <= k <= n+1) are the signed Hultman numbers.

%C "Signed" refers to the fact that these numbers are associated with signed permutations. The numbers themselves are positive.

%H N. Alexeev, A. Pologova, M. A. Alekseyev, Generalized Hultman Numbers and Cycle Structures of Breakpoint Graphs, Journal of Computational Biology 24:2 (2017), 93-105. doi:<a href="http://doi.org/10.1089/cmb.2016.0190">10.1089/cmb.2016.0190</a> arXiv:<a href="http://arxiv.org/abs/1503.05285">1503.05285</a>

%H Simona Grusea and Anthony Labarre, <a href="http://arxiv.org/abs/1104.3353">The distribution of cycles in breakpoint graphs of signed permutations</a>, arXiv:1104.3353v1

%e Triangle begins:

%e 1

%e 1 1

%e 4 3 1

%e 20 21 6 1

%e 148 160 65 10 1

%e 1348 1620 701 155 15 1

%e 15104 19068 9324 2247 315 21 1

%e ...

%Y The first three columns give A001171, A189508, A189509. Cf. A164652.

%K nonn,tabl

%O 0,4

%A _N. J. A. Sloane_, Apr 23 2011

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 July 17 02:47 EDT 2019. Contains 325092 sequences. (Running on oeis4.)