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 | 10 |
| 4 | 39 |
| 5 | 176 |
| 6 | 905 |
| 7 | 5244 |
| 8 | 34111 |
| 9 | 250480 |
| 10 | 2108529 |
| 11 | 20751380 |
| 12 | 241315151 |
| 13 | 3282366504 |
| 14 | 50786289385 |
| 15 | 865850559196 |
| 16 | 15856276032255 |
| 17 | 306665879765984 |
| 18 | 6199863566817761 |
| 19 | 130237717066988580 |
| 20 | 2832527601333186319 |