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 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 24 |
| 5 | 72 |
| 6 | 124 |
| 7 | 210 |
| 8 | 394 |
| 9 | 810 |
| 10 | 1652 |
| 11 | 3168 |
| 12 | 5816 |
| 13 | 10640 |
| 14 | 19794 |
| 15 | 37292 |
| 16 | 70298 |
| 17 | 131618 |
| 18 | 245146 |
| 19 | 456430 |
| 20 | 851670 |
| 21 | 1592008 |
| 22 | 2976326 |
| 23 | 5559808 |
| 24 | 10379010 |
| 25 | 19374184 |
| 26 | 36175422 |
| 27 | 67562524 |
| 28 | 126185322 |
| 29 | 235650426 |
| 30 | 440038528 |