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 | 1 |
| 4 | 4 |
| 5 | 14 |
| 6 | 45 |
| 7 | 140 |
| 8 | 427 |
| 9 | 1288 |
| 10 | 3858 |
| 11 | 11505 |
| 12 | 34210 |
| 13 | 101530 |
| 14 | 300950 |
| 15 | 891345 |
| 16 | 2638650 |
| 17 | 7809000 |
| 18 | 23107488 |
| 19 | 68375547 |
| 20 | 202336092 |
| 21 | 598817490 |
| 22 | 1772479905 |
| 23 | 5247421410 |
| 24 | 15538054455 |
| 25 | 46019183840 |
| 26 | 136325212750 |
| 27 | 403933918375 |
| 28 | 1197131976846 |
| 29 | 3548715207534 |
| 30 | 10521965227669 |