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 | 0 |
| 1 | 1 |
| 2 | 8 |
| 3 | 60 |
| 4 | 464 |
| 5 | 3780 |
| 6 | 32568 |
| 7 | 296492 |
| 8 | 2845088 |
| 9 | 28695060 |
| 10 | 303334920 |
| 11 | 3351877628 |
| 12 | 38622668400 |
| 13 | 463036981732 |
| 14 | 5764038605528 |
| 15 | 74365952622540 |
| 16 | 992720923710272 |
| 17 | 13690497077256628 |
| 18 | 194777994524434344 |
| 19 | 2855149354656290716 |