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) |
|---|---|
| 1 | 0 |
| 2 | 1 |
| 3 | 3 |
| 4 | 15 |
| 5 | 21 |
| 6 | 183 |
| 7 | 309 |
| 8 | 1347 |
| 9 | 4041 |
| 10 | 17163 |
| 11 | 31329 |
| 12 | 149427 |
| 13 | 171081 |
| 14 | 1233963 |
| 15 | 4422609 |
| 16 | 13628187 |
| 17 | 30794481 |
| 18 | 116887923 |
| 19 | 154627929 |
| 20 | 929468907 |
| 21 | 3253991841 |
| 22 | 10227560643 |
| 23 | 26026830729 |
| 24 | 88788949947 |
| 25 | 255658392081 |
| 26 | 820517465043 |
| 27 | 2461552395129 |
| 28 | 7545284051787 |
| 29 | 20547702892161 |