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 | 3 |
| 2 | 12 |
| 3 | 81 |
| 4 | 474 |
| 5 | 2678 |
| 6 | 15410 |
| 7 | 88767 |
| 8 | 510482 |
| 9 | 2936714 |
| 10 | 16895217 |
| 11 | 97197637 |
| 12 | 559175541 |
| 13 | 3216923150 |
| 14 | 18506887013 |
| 15 | 106469709385 |
| 16 | 612517802024 |
| 17 | 3523801014059 |
| 18 | 20272347435052 |
| 19 | 116626354899557 |
| 20 | 670948774602366 |
| 21 | 3859953085161367 |