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 | 5 |
| 3 | 73 |
| 4 | 257 |
| 5 | 1082401 |
| 6 | 4033 |
| 7 | 4432676798593 |
| 8 | 4294967297 |
| 9 | 18014398643699713 |
| 10 | 1098438933505 |
| 11 | 1298708349570020393652962442872833 |
| 12 | 281474959933441 |
| 13 | 91355004067076339167413824240109498970069278721 |