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 | 1 |
| 2 | 3 |
| 3 | 9 |
| 4 | 33 |
| 5 | 135 |
| 6 | 633 |
| 7 | 3207 |
| 8 | 17589 |
| 9 | 102626 |
| 10 | 636014 |
| 11 | 4160852 |
| 12 | 28676800 |
| 13 | 207267046 |
| 14 | 1566709436 |
| 15 | 12337438198 |
| 16 | 100921477976 |
| 17 | 855109095248 |
| 18 | 7488671736398 |
| 19 | 67655656640892 |
| 20 | 629623562927598 |
| 21 | 6027970886933100 |
| 22 | 59306595225701588 |
| 23 | 599011729235408510 |
| 24 | 6205282969563030610 |