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 | 18 |
| 3 | 136 |
| 4 | 1155 |
| 5 | 10530 |
| 6 | 100688 |
| 7 | 996336 |
| 8 | 10116873 |
| 9 | 104819165 |
| 10 | 1103722620 |
| 11 | 11777187240 |
| 12 | 127067830773 |
| 13 | 1383914371728 |
| 14 | 15194457001440 |
| 15 | 167996704221280 |
| 16 | 1868870731122405 |
| 17 | 20903064321375315 |
| 18 | 234927317665726686 |