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 | 1 |
| 2 | 3 |
| 3 | 19 |
| 4 | 171 |
| 5 | 2066 |
| 6 | 31346 |
| 7 | 559987 |
| 8 | 11954993 |
| 9 | 282835456 |
| 10 | 7785919355 |
| 11 | 229359684137 |
| 12 | 7731656573016 |
| 13 | 272633076900991 |
| 14 | 10876116332074739 |
| 15 | 446659746000614675 |
| 16 | 20580725671071449149 |
| 17 | 964732749192326683508 |
| 18 | 50418595763262446272127 |
| 19 | 2656265906893413392905767 |