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) |
|---|---|
| 1 | -1 |
| 2 | 647 |
| 3 | 41471 |
| 4 | 472391 |
| 5 | 2654207 |
| 6 | 10124999 |
| 7 | 30233087 |
| 8 | 76236551 |
| 9 | 169869311 |
| 10 | 344373767 |
| 11 | 647999999 |
| 12 | 1147971527 |
| 13 | 1934917631 |
| 14 | 3127772231 |
| 15 | 4879139327 |
| 16 | 7381124999 |
| 17 | 10871635967 |
| 18 | 15641144711 |
| 19 | 22039921151 |
| 20 | 30485730887 |
| 21 | 41471999999 |
| 22 | 55576446407 |
| 23 | 73470177791 |
| 24 | 95927256071 |
| 25 | 123834728447 |