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 | 0 |
| 3 | 4 |
| 4 | 14 |
| 5 | 29 |
| 6 | 78 |
| 7 | 225 |
| 8 | 632 |
| 9 | 1716 |
| 10 | 4726 |
| 11 | 13482 |
| 12 | 38627 |
| 13 | 112051 |
| 14 | 327426 |
| 15 | 959254 |
| 16 | 2829346 |
| 17 | 8391477 |
| 18 | 24975616 |
| 19 | 74606489 |
| 20 | 223523560 |
| 21 | 671611810 |