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 | 1 |
| 2 | 9 |
| 3 | 49 |
| 4 | 189 |
| 5 | 651 |
| 6 | 2138 |
| 7 | 6847 |
| 8 | 21805 |
| 9 | 69781 |
| 10 | 225260 |
| 11 | 734119 |
| 12 | 2413746 |
| 13 | 7995417 |
| 14 | 26639534 |
| 15 | 89150537 |
| 16 | 299309821 |
| 17 | 1007213417 |
| 18 | 3394930835 |
| 19 | 11456074815 |
| 20 | 38688727608 |
| 21 | 130728462411 |
| 22 | 441894675073 |
| 23 | 1494097644221 |
| 24 | 5052606384210 |
| 25 | 17088501738431 |
| 26 | 57800015328528 |
| 27 | 195513178028053 |