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) |
|---|---|
| 1 | 4 |
| 2 | 10 |
| 3 | 30 |
| 4 | 147 |
| 5 | 408 |
| 6 | 1823 |
| 7 | 4353 |
| 8 | 17690 |
| 9 | 38419 |
| 10 | 143219 |
| 11 | 284441 |
| 12 | 980166 |
| 13 | 1806038 |
| 14 | 5813294 |
| 15 | 10037352 |
| 16 | 30426498 |
| 17 | 49595776 |
| 18 | 142437454 |
| 19 | 220519428 |
| 20 | 603013312 |
| 21 | 890961094 |
| 22 | 2329755538 |