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.

A210911 Number of transitive reflexive early confluent binary relations R on n labeled elements where |{y : xRy}| <= 3 for all x.

Table of values

n a(n)
0 1
1 1
2 4
3 26
4 168
5 1416
6 13897
7 153126
8 1893180
9 25796852
10 383636151
11 6177688914
12 106969864696
13 1980478817526
14 39015578535585
15 814416108606566
16 17947777613632128
17 416233580676722424
18 10129555365300697267
19 258028441032419619786
20 6864011282184757297896

List of values

[1, 1, 4, 26, 168, 1416, 13897, 153126, 1893180, 25796852, 383636151, 6177688914, 106969864696, 1980478817526, 39015578535585, 814416108606566, 17947777613632128, 416233580676722424, 10129555365300697267, 258028441032419619786, 6864011282184757297896]

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

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