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) |
|---|---|
| 1 | 2 |
| 2 | 6 |
| 3 | 12 |
| 4 | 70 |
| 5 | 102 |
| 6 | 540 |
| 7 | 1090 |
| 8 | 1366 |
| 9 | 1626 |
| 10 | 4176 |
| 11 | 9010 |
| 12 | 9550 |
| 13 | 36912 |
| 14 | 43062 |
| 15 | 49680 |
| 16 | 57916 |
| 17 | 483610 |
| 18 | 877842 |
| 19 | 2215302 |
| 20 | 2704980 |
| 21 | 3598866 |
| 22 | 7973130 |
| 23 | 8530116 |