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 | 7 |
| 2 | 47 |
| 3 | 317 |
| 4 | 2137 |
| 5 | 14407 |
| 6 | 97127 |
| 7 | 654797 |
| 8 | 4414417 |
| 9 | 29760487 |
| 10 | 200635007 |
| 11 | 1352612477 |
| 12 | 9118849897 |
| 13 | 61476161767 |
| 14 | 414451220087 |
| 15 | 2794088129357 |
| 16 | 18836784876577 |
| 17 | 126991149906247 |
| 18 | 856130823820367 |
| 19 | 5771740692453437 |
| 20 | 38911098273822457 |
| 21 | 262325293105201927 |