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 | 0 |
| 2 | 1 |
| 3 | 48 |
| 4 | 603 |
| 5 | 5158 |
| 6 | 37257 |
| 7 | 247236 |
| 8 | 1568215 |
| 9 | 9703890 |
| 10 | 59226357 |
| 11 | 358722928 |
| 12 | 2163496611 |
| 13 | 13017647646 |
| 14 | 78225458401 |
| 15 | 469740168924 |
| 16 | 2819689366191 |
| 17 | 16922139539626 |
| 18 | 101545622110989 |
| 19 | 609314411814024 |
| 20 | 3656015481903355 |
| 21 | 21936500845191030 |
| 22 | 131620291694585721 |