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 | 12 |
| 2 | 102 |
| 3 | 812 |
| 4 | 6402 |
| 5 | 50412 |
| 6 | 396902 |
| 7 | 3124812 |
| 8 | 24601602 |
| 9 | 193688012 |
| 10 | 1524902502 |
| 11 | 12005532012 |
| 12 | 94519353602 |
| 13 | 744149296812 |
| 14 | 5858675020902 |
| 15 | 46125250870412 |
| 16 | 363143331942402 |
| 17 | 2859021404668812 |
| 18 | 22509027905408102 |
| 19 | 177213201838596012 |
| 20 | 1395196586803360002 |
| 21 | 10984359492588284012 |