cp's OEIS Frontend

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.

A328425 Number of inversion sequences of length n where all consecutive subsequences i,j,k satisfy i < j > k or i >= j <= k.

Table of values

n a(n)
0 1
1 1
2 2
3 4
4 11
5 36
6 142
7 647
8 3383
9 19816
10 129162
11 923279
12 7201951
13 60720996
14 551268926
15 5352973967
16 55430433719
17 609033864160
18 7083303687843
19 86864585123112
20 1120997775904467
21 15176639841694385
22 215196709973260722
23 3187766448289854016
24 49262381105608795771

List of values

[1, 1, 2, 4, 11, 36, 142, 647, 3383, 19816, 129162, 923279, 7201951, 60720996, 551268926, 5352973967, 55430433719, 609033864160, 7083303687843, 86864585123112, 1120997775904467, 15176639841694385, 215196709973260722, 3187766448289854016, 49262381105608795771]

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

Content is available under The OEIS End-User License Agreement.