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 | 4 |
| 4 | 13 |
| 5 | 40 |
| 6 | 120 |
| 7 | 352 |
| 8 | 1022 |
| 9 | 2948 |
| 10 | 8473 |
| 11 | 24304 |
| 12 | 69649 |
| 13 | 199544 |
| 14 | 571795 |
| 15 | 1639244 |
| 16 | 4702499 |
| 17 | 13500396 |
| 18 | 38790727 |
| 19 | 111555296 |
| 20 | 321100627 |
| 21 | 925086012 |
| 22 | 2667533646 |
| 23 | 7698716068 |
| 24 | 22238169212 |
| 25 | 64289860528 |
| 26 | 186010834243 |
| 27 | 538611262492 |