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 | 0 |
| 1 | 1 |
| 2 | 2 |
| 3 | 5 |
| 4 | 15 |
| 5 | 47 |
| 6 | 156 |
| 7 | 527 |
| 8 | 1826 |
| 9 | 6407 |
| 10 | 22762 |
| 11 | 81587 |
| 12 | 294711 |
| 13 | 1070973 |
| 14 | 3912808 |
| 15 | 14358493 |
| 16 | 52893647 |
| 17 | 195498831 |
| 18 | 724704974 |
| 19 | 2693397035 |
| 20 | 10033263089 |
| 21 | 37452388361 |
| 22 | 140063288728 |