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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.

A321277 One half of the sum over all permutations of [n] of the absolute difference between the length of the longest increasing subsequence and the length of the longest decreasing subsequence.

Table of values

n a(n)
1 0
2 1
3 2
4 12
5 61
6 367
7 2805
8 23372
9 213317
10 2189823
11 24882811
12 305633678
13 4037554628
14 57447084699
15 877263905683
16 14276260437624
17 246201450585329
18 4487236144246511
19 86286209907252739
20 1746559569805617910
21 37106502447954647906
22 825196425771658993531

List of values

[0, 1, 2, 12, 61, 367, 2805, 23372, 213317, 2189823, 24882811, 305633678, 4037554628, 57447084699, 877263905683, 14276260437624, 246201450585329, 4487236144246511, 86286209907252739, 1746559569805617910, 37106502447954647906, 825196425771658993531]

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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