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 | 0 |
| 1 | 0 |
| 2 | 1 |
| 3 | 3 |
| 4 | 9 |
| 5 | 24 |
| 6 | 62 |
| 7 | 156 |
| 8 | 387 |
| 9 | 951 |
| 10 | 2323 |
| 11 | 5652 |
| 12 | 13716 |
| 13 | 33228 |
| 14 | 80405 |
| 15 | 194415 |
| 16 | 469845 |
| 17 | 1135092 |
| 18 | 2741626 |
| 19 | 6620928 |
| 20 | 15987663 |
| 21 | 38603019 |
| 22 | 93204647 |
| 23 | 225030024 |
| 24 | 543293352 |
| 25 | 1311663096 |
| 26 | 3166694569 |
| 27 | 7645173627 |
| 28 | 18457238241 |
| 29 | 44559967920 |
| 30 | 107577688310 |
| 31 | 259716176580 |