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 | 5 |
| 2 | 33 |
| 3 | 229 |
| 4 | 1601 |
| 5 | 11205 |
| 6 | 78433 |
| 7 | 549029 |
| 8 | 3843201 |
| 9 | 26902405 |
| 10 | 188316833 |
| 11 | 1318217829 |
| 12 | 9227524801 |
| 13 | 64592673605 |
| 14 | 452148715233 |
| 15 | 3165041006629 |
| 16 | 22155287046401 |
| 17 | 155087009324805 |
| 18 | 1085609065273633 |
| 19 | 7599263456915429 |
| 20 | 53194844198408001 |