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 | 13 |
| 2 | 98 |
| 3 | 560 |
| 4 | 2688 |
| 5 | 11424 |
| 6 | 44352 |
| 7 | 160512 |
| 8 | 549120 |
| 9 | 1793792 |
| 10 | 5637632 |
| 11 | 17145856 |
| 12 | 50692096 |
| 13 | 146227200 |
| 14 | 412778496 |
| 15 | 1143078912 |
| 16 | 3111714816 |
| 17 | 8341487616 |
| 18 | 22052208640 |
| 19 | 57567870976 |
| 20 | 148562247680 |
| 21 | 379364311040 |
| 22 | 959384125440 |