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 | 3 |
| 3 | 14 |
| 4 | 82 |
| 5 | 579 |
| 6 | 4741 |
| 7 | 43977 |
| 8 | 454283 |
| 9 | 5159441 |
| 10 | 63782411 |
| 11 | 851368766 |
| 12 | 12188927818 |
| 13 | 186132043831 |
| 14 | 3017325884473 |
| 15 | 51712139570022 |
| 16 | 933654684562038 |
| 17 | 17702959714232057 |
| 18 | 351535449888420187 |
| 19 | 7292626296788508624 |
| 20 | 157698798590301690864 |
| 21 | 3547597554377118966359 |