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 | 13 |
| 2 | 253 |
| 3 | 273 |
| 4 | 52919 |
| 5 | 11375 |
| 6 | 3074653 |
| 7 | 470197 |
| 8 | 90422639 |
| 9 | 19283355 |
| 10 | 8126686265 |
| 11 | 784744961 |
| 12 | 13628116788869 |
| 13 | 31697064295 |
| 14 | 1205409115771 |
| 15 | 1271113717965 |
| 16 | 4094611999396543 |
| 17 | 50626609919795 |
| 18 | 254342027061912151 |
| 19 | 2003431460774809 |
| 20 | 4149481162406543989 |