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 | 3 |
| 2 | 10 |
| 3 | 34 |
| 4 | 120 |
| 5 | 434 |
| 6 | 1596 |
| 7 | 5940 |
| 8 | 22308 |
| 9 | 84370 |
| 10 | 320892 |
| 11 | 1226108 |
| 12 | 4702880 |
| 13 | 18097044 |
| 14 | 69832600 |
| 15 | 270118440 |
| 16 | 1047043260 |
| 17 | 4066132050 |
| 18 | 15816664380 |
| 19 | 61615392300 |
| 20 | 240347793840 |
| 21 | 938669220060 |
| 22 | 3669940053000 |