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A189507 Triangle read by rows: T(n,k) (n >= 0, 1 <= k <= n+1) are the signed Hultman numbers. 7
1, 1, 1, 4, 3, 1, 20, 21, 6, 1, 148, 160, 65, 10, 1, 1348, 1620, 701, 155, 15, 1, 15104, 19068, 9324, 2247, 315, 21, 1, 198144, 264420, 138016, 38029, 5908, 574, 28, 1, 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, 1 (list; table; graph; refs; listen; history; text; internal format)
OFFSET
0,4
COMMENTS
"Signed" refers to the fact that these numbers are associated with signed permutations. The numbers themselves are positive.
LINKS
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:10.1089/cmb.2016.0190 arXiv:1503.05285
Simona Grusea and Anthony Labarre, The distribution of cycles in breakpoint graphs of signed permutations, arXiv:1104.3353v1
EXAMPLE
Triangle begins:
1
1 1
4 3 1
20 21 6 1
148 160 65 10 1
1348 1620 701 155 15 1
15104 19068 9324 2247 315 21 1
...
CROSSREFS
The first three columns give A001171, A189508, A189509. Cf. A164652.
Sequence in context: A193795 A181355 A128320 * A348436 A350528 A208057
KEYWORD
nonn,tabl
AUTHOR
N. J. A. Sloane, Apr 23 2011
STATUS
approved

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Last modified April 18 06:24 EDT 2024. Contains 371769 sequences. (Running on oeis4.)