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 | 0 |
| 1 | 1 |
| 2 | 45 |
| 3 | 420 |
| 4 | 2048 |
| 5 | 6987 |
| 6 | 19047 |
| 7 | 44467 |
| 8 | 92681 |
| 9 | 177147 |
| 10 | 316227 |
| 11 | 534145 |
| 12 | 861979 |
| 13 | 1338715 |
| 14 | 2012353 |
| 15 | 2941046 |
| 16 | 4194304 |
| 17 | 5854220 |
| 18 | 8016758 |
| 19 | 10793065 |
| 20 | 14310835 |
| 21 | 18715701 |
| 22 | 24172676 |
| 23 | 30867616 |
| 24 | 39008731 |
| 25 | 48828125 |
| 26 | 60583368 |
| 27 | 74559107 |