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 | 2 |
| 3 | 8 |
| 4 | 34 |
| 5 | 136 |
| 6 | 538 |
| 7 | 2080 |
| 8 | 7970 |
| 9 | 30224 |
| 10 | 113874 |
| 11 | 426520 |
| 12 | 1590338 |
| 13 | 5906640 |
| 14 | 21866794 |
| 15 | 80725280 |
| 16 | 297292610 |
| 17 | 1092539736 |
| 18 | 4007553922 |
| 19 | 14675748416 |
| 20 | 53663197698 |
| 21 | 195962433328 |
| 22 | 714734393378 |
| 23 | 2603994002280 |
| 24 | 9477643739746 |
| 25 | 34463730424720 |