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 | 3 |
| 2 | 23 |
| 3 | 191 |
| 4 | 1727 |
| 5 | 17279 |
| 6 | 207359 |
| 7 | 2903039 |
| 8 | 43545599 |
| 9 | 696729599 |
| 10 | 12541132799 |
| 11 | 250822655999 |
| 12 | 5267275775999 |
| 13 | 115880067071999 |
| 14 | 2781121609727999 |
| 15 | 69528040243199999 |
| 16 | 1807729046323199999 |
| 17 | 48808684250726399999 |
| 18 | 1366643159020339199999 |