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 | 0 |
| 4 | 0 |
| 5 | 1 |
| 6 | 3 |
| 7 | 8 |
| 8 | 22 |
| 9 | 63 |
| 10 | 157 |
| 11 | 502 |
| 12 | 1562 |
| 13 | 4688 |
| 14 | 15533 |
| 15 | 50953 |
| 16 | 165054 |
| 17 | 562376 |
| 18 | 1911007 |
| 19 | 6467143 |
| 20 | 22447463 |
| 21 | 78021923 |
| 22 | 271410289 |
| 23 | 957082911 |
| 24 | 3384587525 |
| 25 | 11998851674 |
| 26 | 42876440587 |
| 27 | 153684701645 |
| 28 | 552421854011 |
| 29 | 1995875594696 |
| 30 | 7231871165277 |
| 31 | 26274832876337 |