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 | 5 |
| 3 | 1 |
| 4 | 251 |
| 5 | 19 |
| 6 | 19087 |
| 7 | 751 |
| 8 | 1070017 |
| 9 | 2857 |
| 10 | 26842253 |
| 11 | 434293 |
| 12 | 703604254357 |
| 13 | 8181904909 |
| 14 | 1166309819657 |
| 15 | 5044289 |
| 16 | 8092989203533249 |
| 17 | 5026792806787 |
| 18 | 12600467236042756559 |
| 19 | 69028763155644023 |
| 20 | 8136836498467582599787 |