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.

A272431 Number of ordered set partitions of {1,2,...,n} such that no part has the same size as any of its three immediate predecessors.

Table of values

n a(n)
0 1
1 1
2 1
3 7
4 9
5 31
6 403
7 757
8 2873
9 12607
10 333051
11 1592977
12 10684875
13 105031681
14 697538325
15 8987362027
16 114294624633
17 975751249951
18 14157072527947
19 124133073947209
20 2048876740991939
21 36859613739949357
22 443133109281574185
23 6166869485798451019

List of values

[1, 1, 1, 7, 9, 31, 403, 757, 2873, 12607, 333051, 1592977, 10684875, 105031681, 697538325, 8987362027, 114294624633, 975751249951, 14157072527947, 124133073947209, 2048876740991939, 36859613739949357, 443133109281574185, 6166869485798451019]

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

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