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 | 31 |
| 4 | 215 |
| 5 | 1597 |
| 6 | 12425 |
| 7 | 99955 |
| 8 | 824675 |
| 9 | 6939769 |
| 10 | 59334605 |
| 11 | 513972967 |
| 12 | 4501041935 |
| 13 | 39784038517 |
| 14 | 354455513105 |
| 15 | 3179928556219 |
| 16 | 28701561707675 |
| 17 | 260447708523505 |
| 18 | 2374690737067925 |
| 19 | 21744508765633327 |
| 20 | 199877846477679815 |
| 21 | 1843718766426242221 |
| 22 | 17060955558786455705 |
| 23 | 158333204443000060291 |