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) |
|---|---|
| 2 | 1 |
| 3 | 12 |
| 4 | 84 |
| 5 | 468 |
| 6 | 2332 |
| 7 | 11068 |
| 8 | 51472 |
| 9 | 237832 |
| 10 | 1095384 |
| 11 | 5040568 |
| 12 | 23168528 |
| 13 | 106496816 |
| 14 | 489379904 |
| 15 | 2250000884 |
| 16 | 10345888480 |
| 17 | 47604198576 |
| 18 | 219096141188 |
| 19 | 1009071461380 |
| 20 | 4648802248764 |
| 21 | 21431064157200 |
| 22 | 98828123716260 |