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) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 6 |
| 3 | 10 |
| 4 | 70 |
| 5 | 42 |
| 6 | 462 |
| 7 | 858 |
| 8 | 4290 |
| 9 | 24310 |
| 10 | 92378 |
| 11 | 176358 |
| 12 | 1352078 |
| 13 | 520030 |
| 14 | 222870 |
| 15 | 6463230 |
| 16 | 200360130 |
| 17 | 129644790 |
| 18 | 907513530 |
| 19 | 1767263190 |
| 20 | 22974421470 |
| 21 | 134564468610 |
| 22 | 526024740930 |
| 23 | 22870640910 |
| 24 | 1074920122770 |
| 25 | 1504888171878 |
| 26 | 1967930686302 |
| 27 | 34766775458002 |
| 28 | 1912172650190110 |