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 | 3 |
| 2 | 11 |
| 3 | 37 |
| 4 | 123 |
| 5 | 411 |
| 6 | 1371 |
| 7 | 4572 |
| 8 | 15241 |
| 9 | 50805 |
| 10 | 169350 |
| 11 | 564502 |
| 12 | 1881676 |
| 13 | 6272254 |
| 14 | 20907515 |
| 15 | 69691719 |
| 16 | 232305731 |
| 17 | 774352437 |
| 18 | 2581174791 |
| 19 | 8603915972 |
| 20 | 28679719907 |
| 21 | 95599066359 |
| 22 | 318663554532 |
| 23 | 1062211848441 |
| 24 | 3540706161472 |