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.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 6 |
| 5 | 12 |
| 6 | 28 |
| 7 | 76 |
| 8 | 240 |
| 9 | 852 |
| 10 | 3392 |
| 11 | 14868 |
| 12 | 71392 |
| 13 | 371740 |
| 14 | 2089184 |
| 15 | 12589980 |
| 16 | 81037792 |
| 17 | 554555300 |
| 18 | 4021728992 |
| 19 | 30800978980 |
| 20 | 248464000480 |
| 21 | 2105271605804 |
| 22 | 18696216008416 |
| 23 | 173630895701996 |
| 24 | 1683187452989920 |
| 25 | 17000599430003444 |
| 26 | 178625854452674272 |