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.

A303027 Number of free pure symmetric multifunctions with one atom, n positions, and no empty or unitary parts (subexpressions of the form x[] or x[y]).

Table of values

n a(n)
1 1
2 0
3 0
4 1
5 1
6 1
7 3
8 5
9 7
10 15
11 28
12 47
13 90
14 175
15 319
16 607
17 1181
18 2251
19 4325
20 8449
21 16425
22 31992
23 62823
24 123521
25 243047
26 480316
27 951290
28 1886293
29 3749341
30 7467815
31 14893500
32 29752398
33 59532947
34 119274491
35 239275400
36 480638121
37 966571853
38 1945901716
39 3921699524

List of values

[1, 0, 0, 1, 1, 1, 3, 5, 7, 15, 28, 47, 90, 175, 319, 607, 1181, 2251, 4325, 8449, 16425, 31992, 62823, 123521, 243047, 480316, 951290, 1886293, 3749341, 7467815, 14893500, 29752398, 59532947, 119274491, 239275400, 480638121, 966571853, 1945901716, 3921699524]

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

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