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 | 3 |
| 3 | 14 |
| 4 | 78 |
| 5 | 475 |
| 6 | 3057 |
| 7 | 20446 |
| 8 | 140702 |
| 9 | 989789 |
| 10 | 7085635 |
| 11 | 51451482 |
| 12 | 378049810 |
| 13 | 2805616460 |
| 14 | 20999408480 |
| 15 | 158337719608 |
| 16 | 1201585477436 |
| 17 | 9170328295222 |
| 18 | 70339328959266 |
| 19 | 541953619822062 |
| 20 | 4192560258116202 |
| 21 | 32552250308843605 |
| 22 | 253583917423039079 |