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 | 1 |
| 1 | 4 |
| 2 | 26 |
| 3 | 249 |
| 4 | 3274 |
| 5 | 56135 |
| 6 | 1207433 |
| 7 | 31638625 |
| 8 | 987249425 |
| 9 | 36030130677 |
| 10 | 1515621707692 |
| 11 | 72603595393584 |
| 12 | 3920675798922189 |
| 13 | 236615520916677436 |
| 14 | 15840357595697061964 |
| 15 | 1168697367186883073296 |
| 16 | 94486667847573203169757 |
| 17 | 8328527812527985862657297 |
| 18 | 796762955545266206229493979 |