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 | 16 |
| 4 | 71 |
| 5 | 336 |
| 6 | 1660 |
| 7 | 8464 |
| 8 | 44207 |
| 9 | 235306 |
| 10 | 1271807 |
| 11 | 6961307 |
| 12 | 38508659 |
| 13 | 214950425 |
| 14 | 1209170536 |
| 15 | 6848080767 |
| 16 | 39014400171 |
| 17 | 223439516338 |
| 18 | 1285660965508 |
| 19 | 7428738358924 |
| 20 | 43087099589998 |
| 21 | 250766507928988 |
| 22 | 1464026402082801 |