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 | 12 |
| 2 | 223 |
| 3 | 3898 |
| 4 | 64453 |
| 5 | 1042868 |
| 6 | 16747743 |
| 7 | 268285422 |
| 8 | 4294211881 |
| 9 | 68715706984 |
| 10 | 1099492954547 |
| 11 | 17592094126818 |
| 12 | 281474526684989 |
| 13 | 4503597434338652 |
| 14 | 72057583394694855 |
| 15 | 1152921453139596758 |
| 16 | 18446743825630274641 |
| 17 | 295147903987017778256 |
| 18 | 4722366477153821698011 |