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 | 4 |
| 3 | 17 |
| 4 | 76 |
| 5 | 352 |
| 6 | 1674 |
| 7 | 8129 |
| 8 | 40156 |
| 9 | 201236 |
| 10 | 1020922 |
| 11 | 5234660 |
| 12 | 27089726 |
| 13 | 141335846 |
| 14 | 742712598 |
| 15 | 3927908193 |
| 16 | 20891799036 |
| 17 | 111688381228 |
| 18 | 599841215226 |
| 19 | 3234957053984 |
| 20 | 17512055200470 |
| 21 | 95125188934942 |
| 22 | 518340392855286 |
| 23 | 2832580291316092 |
| 24 | 15520177744727766 |