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 | 3 |
| 3 | 7 |
| 4 | 16 |
| 5 | 39 |
| 6 | 105 |
| 7 | 315 |
| 8 | 1048 |
| 9 | 3829 |
| 10 | 15207 |
| 11 | 65071 |
| 12 | 297840 |
| 13 | 1449755 |
| 14 | 7468541 |
| 15 | 40555747 |
| 16 | 231335960 |
| 17 | 1381989881 |
| 18 | 8623700811 |
| 19 | 56078446615 |
| 20 | 379233142800 |
| 21 | 2662013133295 |
| 22 | 19362917622001 |
| 23 | 145719550012299 |
| 24 | 1133023004941272 |
| 25 | 9090156910550109 |
| 26 | 75161929739797519 |