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 | 1 |
| 2 | 4 |
| 3 | 17 |
| 4 | 78 |
| 5 | 382 |
| 6 | 1975 |
| 7 | 10663 |
| 8 | 59526 |
| 9 | 340802 |
| 10 | 1988575 |
| 11 | 11771619 |
| 12 | 70465201 |
| 13 | 425572175 |
| 14 | 2589083577 |
| 15 | 15849320663 |
| 16 | 97548380006 |
| 17 | 603277351699 |
| 18 | 3747168602548 |
| 19 | 23367880883262 |
| 20 | 146262143795248 |
| 21 | 918597886652632 |
| 22 | 5787577778959613 |
| 23 | 36572319110701681 |
| 24 | 231742772456205071 |