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 | 2 |
| 4 | 4 |
| 5 | 14 |
| 6 | 38 |
| 7 | 132 |
| 8 | 420 |
| 9 | 1426 |
| 10 | 4834 |
| 11 | 16796 |
| 12 | 58688 |
| 13 | 208012 |
| 14 | 742636 |
| 15 | 2674384 |
| 16 | 9693976 |
| 17 | 35357670 |
| 18 | 129641774 |
| 19 | 477638700 |
| 20 | 1767253368 |
| 21 | 6564119892 |
| 22 | 24466233428 |
| 23 | 91482563640 |
| 24 | 343059494120 |
| 25 | 1289904147128 |
| 26 | 4861945985428 |
| 27 | 18367353066440 |
| 28 | 69533549429280 |
| 29 | 263747951750360 |