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) |
|---|---|
| 4 | 2 |
| 5 | 10 |
| 6 | 48 |
| 7 | 180 |
| 8 | 570 |
| 9 | 1602 |
| 10 | 4128 |
| 11 | 9972 |
| 12 | 22947 |
| 13 | 50899 |
| 14 | 109806 |
| 15 | 231988 |
| 16 | 482540 |
| 17 | 992212 |
| 18 | 2023184 |
| 19 | 4100632 |
| 20 | 8275877 |
| 21 | 16652701 |
| 22 | 33439998 |
| 23 | 67057096 |
| 24 | 134344422 |
| 25 | 268984854 |
| 26 | 538346448 |
| 27 | 1077167916 |
| 28 | 2154929607 |
| 29 | 4310595495 |