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 | 4 |
| 2 | 18 |
| 3 | 60 |
| 4 | 195 |
| 5 | 576 |
| 6 | 1644 |
| 7 | 4488 |
| 8 | 11925 |
| 9 | 30860 |
| 10 | 78278 |
| 11 | 195012 |
| 12 | 478599 |
| 13 | 1159080 |
| 14 | 2774880 |
| 15 | 6575280 |
| 16 | 15439065 |
| 17 | 35955540 |
| 18 | 83118970 |
| 19 | 190862860 |
| 20 | 435601611 |
| 21 | 988620624 |
| 22 | 2232236628 |
| 23 | 5016441240 |
| 24 | 11224087965 |