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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.

A135312 Number of transitive reflexive binary relations R on n labeled elements where |{y : xRy}| <= 2 for all x.

Table of values

n a(n)
0 1
1 1
2 4
3 13
4 62
5 311
6 1822
7 11593
8 80964
9 608833
10 4910786
11 42159239
12 383478988
13 3678859159
14 37087880754
15 391641822541
16 4319860660448
17 49647399946049
18 593217470459314
19 7354718987639959
20 94445777492433516
21 1254196823154143191
22 17198114810490326714
23 243191242578584519333

List of values

[1, 1, 4, 13, 62, 311, 1822, 11593, 80964, 608833, 4910786, 42159239, 383478988, 3678859159, 37087880754, 391641822541, 4319860660448, 49647399946049, 593217470459314, 7354718987639959, 94445777492433516, 1254196823154143191, 17198114810490326714, 243191242578584519333]

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

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