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 | 1 |
| 2 | 3 |
| 3 | 9 |
| 4 | 72 |
| 5 | 612 |
| 6 | 6381 |
| 7 | 34191 |
| 8 | 375201 |
| 9 | 3065211 |
| 10 | 3365919 |
| 11 | 75779001 |
| 12 | 300733722 |
| 13 | 661102209 |
| 14 | 7266033891 |
| 15 | 37610189712 |
| 16 | 631965038211 |
| 17 | 3364115985981 |
| 18 | 34975974329001 |
| 19 | 300789229729401 |
| 20 | 302881986763209 |
| 21 | 726982069546809 |