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 | 121 |
| 5 | 1041 |
| 6 | 10651 |
| 7 | 121843 |
| 8 | 1575729 |
| 9 | 22970881 |
| 10 | 366805171 |
| 11 | 6365365491 |
| 12 | 120044573353 |
| 13 | 2430782532049 |
| 14 | 52677233993931 |
| 15 | 1217023986185491 |
| 16 | 29799465317716321 |
| 17 | 771272544315151233 |
| 18 | 21044341084622337379 |
| 19 | 603173026772647474771 |