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 | 5 |
| 3 | 44 |
| 4 | 321 |
| 5 | 2404 |
| 6 | 14692 |
| 7 | 98831 |
| 8 | 684729 |
| 9 | 4642752 |
| 10 | 31650422 |
| 11 | 213894450 |
| 12 | 1451388234 |
| 13 | 9868405649 |
| 14 | 66968132029 |
| 15 | 454745989239 |
| 16 | 3086695784357 |
| 17 | 20954497956277 |
| 18 | 142275120134328 |
| 19 | 965860855067492 |
| 20 | 6557295186301572 |
| 21 | 44517125016379779 |
| 22 | 302224231486908372 |