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) |
|---|---|
| 3 | 0 |
| 4 | 10 |
| 5 | 47 |
| 6 | 157 |
| 7 | 503 |
| 8 | 1669 |
| 9 | 5472 |
| 10 | 17531 |
| 11 | 55135 |
| 12 | 172134 |
| 13 | 535510 |
| 14 | 1660795 |
| 15 | 5133470 |
| 16 | 15826173 |
| 17 | 48706210 |
| 18 | 149721544 |
| 19 | 459820058 |
| 20 | 1411142937 |
| 21 | 4328181110 |
| 22 | 13269541967 |
| 23 | 40669595890 |
| 24 | 124617708274 |
| 25 | 381776661185 |
| 26 | 1169438884559 |
| 27 | 3581781480980 |
| 28 | 10969462410857 |
| 29 | 33592685042253 |