This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A115755 #12 Feb 24 2020 04:26:28 %S A115755 1,1,1,1,3,2,1,6,15,2,1,10,51,56,2,1,15,127,390,185,2,1,21,263,1562, %T A115755 2543,648,2,1,28,483,4635,16445,16615,2111,2,1,36,820,11407,69863, %U A115755 169034,105365,6352,2 %N A115755 Number of permutations of n elements whose unsigned reversal distance is k. %C A115755 Probably an erroneous version of A300003. Some inner terms of the triangle differ slightly. Sean A. Irvine reread the paper and checked manually that a(13) should be 52. The last row 1, 36, 820 ... 6352, 2 was added later and is ok. - _Georg Fischer_, Feb 24 2020 %H A115755 J. D. Kececioglu, and D. Sankoff, <a href="https://www.researchgate.net/publication/226954865_Exact_and_Approximation_Algorithms_for_Sorting_by_Reversals_with_Application_to_Genome_Rearrangement">Exact and approximation algorithms for sorting by reversals, with application to genome rearrangement</a>, Algorithmica (1995) 13:180. %e A115755 a(3,1) = 3 because the only three permutations of S_3 that require exactly one reversal to be sorted are (1 3 2), (2 1 3) and (3 2 1). %Y A115755 Cf. A300003. %K A115755 nonn,tabl %O A115755 1,5 %A A115755 _Anthony Labarre_, Mar 29 2006, Jun 03 2006