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 | 14 |
| 4 | 84 |
| 5 | 596 |
| 6 | 4785 |
| 7 | 42349 |
| 8 | 406287 |
| 9 | 4176971 |
| 10 | 45640572 |
| 11 | 526788153 |
| 12 | 6392402793 |
| 13 | 81247489335 |
| 14 | 1078331283648 |
| 15 | 14907041720241 |
| 16 | 214187010762831 |
| 17 | 3192620516380376 |
| 18 | 49287883925072010 |
| 19 | 786925082232918304 |
| 20 | 12976244331714379149 |
| 21 | 220728563512663520510 |