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 | 1 |
| 1 | 9 |
| 2 | 54 |
| 3 | 273 |
| 4 | 1197 |
| 5 | 4761 |
| 6 | 17577 |
| 7 | 60957 |
| 8 | 200799 |
| 9 | 633007 |
| 10 | 1920510 |
| 11 | 5633667 |
| 12 | 16037700 |
| 13 | 44439840 |
| 14 | 120165858 |
| 15 | 317762553 |
| 16 | 823240341 |
| 17 | 2092864401 |
| 18 | 5228118701 |
| 19 | 12848849154 |
| 20 | 31100190048 |
| 21 | 74208885351 |
| 22 | 174708121455 |
| 23 | 406132690635 |
| 24 | 932871440739 |
| 25 | 2118595079790 |
| 26 | 4759875472491 |