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 | 19 |
| 4 | 219 |
| 5 | 3991 |
| 6 | 106623 |
| 7 | 3964339 |
| 8 | 199515459 |
| 9 | 13399883551 |
| 10 | 1197639892983 |
| 11 | 143076298623259 |
| 12 | 23053861370437659 |
| 13 | 5062745845287855271 |
| 14 | 1530139311543346178223 |
| 15 | 641441466132460086890179 |
| 16 | 375107113287994040621904819 |
| 17 | 307244526491924695346004951151 |
| 18 | 353511145615118063468292270299943 |