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 | 1 |
| 2 | 5 |
| 3 | 30 |
| 4 | 205 |
| 5 | 1476 |
| 6 | 11070 |
| 7 | 85410 |
| 8 | 672605 |
| 9 | 5380830 |
| 10 | 43584804 |
| 11 | 356602950 |
| 12 | 2941974270 |
| 13 | 24441017580 |
| 14 | 204257075490 |
| 15 | 1715759433624 |
| 16 | 14476720225405 |
| 17 | 122626336026960 |
| 18 | 1042323856225470 |
| 19 | 8887182353111790 |
| 20 | 75985409119105764 |
| 21 | 651303506735164140 |
| 22 | 5595289216952336550 |