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 | 5 |
| 2 | 13 |
| 3 | 39 |
| 4 | 102 |
| 5 | 272 |
| 6 | 712 |
| 7 | 1869 |
| 8 | 4893 |
| 9 | 12815 |
| 10 | 33550 |
| 11 | 87840 |
| 12 | 229968 |
| 13 | 602069 |
| 14 | 1576237 |
| 15 | 4126647 |
| 16 | 10803702 |
| 17 | 28284464 |
| 18 | 74049688 |
| 19 | 193864605 |
| 20 | 507544125 |
| 21 | 1328767775 |
| 22 | 3478759198 |
| 23 | 9107509824 |
| 24 | 23843770272 |
| 25 | 62423800997 |
| 26 | 163427632717 |