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) |
|---|---|
| 2 | 1 |
| 3 | 22 |
| 4 | 155 |
| 5 | 709 |
| 6 | 2587 |
| 7 | 8273 |
| 8 | 24416 |
| 9 | 68595 |
| 10 | 187030 |
| 11 | 500950 |
| 12 | 1327986 |
| 13 | 3499982 |
| 14 | 9195035 |
| 15 | 24115804 |
| 16 | 63192397 |
| 17 | 165512723 |
| 18 | 433410661 |
| 19 | 1134800215 |
| 20 | 2971089810 |
| 21 | 7778591025 |
| 22 | 20364830496 |
| 23 | 53316076892 |
| 24 | 139583609940 |
| 25 | 365435000524 |
| 26 | 956721681957 |
| 27 | 2504730383698 |
| 28 | 6557469861231 |