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 | 3 |
| 3 | 7 |
| 4 | 23 |
| 5 | 151 |
| 6 | 4247 |
| 7 | 1052823 |
| 8 | 8590987415 |
| 9 | 18014407100469399 |
| 10 | 309485009839359475825250455 |
| 11 | 11150372599265311880252868975683656578240663 |
| 12 | 6901746346790563787434755873427398051716420852423255530846180802039959 |