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 | 0 |
| 1 | 1 |
| 2 | 3 |
| 3 | 9 |
| 4 | 45 |
| 5 | 185 |
| 6 | 1277 |
| 7 | 7469 |
| 8 | 67993 |
| 9 | 514841 |
| 10 | 5414197 |
| 11 | 52609653 |
| 12 | 679432169 |
| 13 | 7704502013 |
| 14 | 111283754969 |
| 15 | 1515535050805 |
| 16 | 25257251330321 |
| 17 | 385282195339393 |
| 18 | 7088110874426409 |
| 19 | 123325149268482781 |
| 20 | 2520808658222616653 |
| 21 | 48623257343586890769 |
| 22 | 1078165538033926164281 |