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 | 3 |
| 2 | 15 |
| 3 | 109 |
| 4 | 1053 |
| 5 | 12711 |
| 6 | 184123 |
| 7 | 3111585 |
| 8 | 60096249 |
| 9 | 1305766603 |
| 10 | 31523994471 |
| 11 | 837162204693 |
| 12 | 24253060182805 |
| 13 | 761176868685039 |
| 14 | 25727009276451603 |
| 15 | 931657420717406281 |
| 16 | 35987519689305385713 |
| 17 | 1476986487871517622675 |