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) |
|---|---|
| 1 | 1 |
| 2 | 0 |
| 3 | 1 |
| 4 | 1 |
| 5 | 3 |
| 6 | 7 |
| 7 | 16 |
| 8 | 45 |
| 9 | 110 |
| 10 | 308 |
| 11 | 819 |
| 12 | 2275 |
| 13 | 6328 |
| 14 | 17748 |
| 15 | 50388 |
| 16 | 143412 |
| 17 | 411939 |
| 18 | 1187329 |
| 19 | 3441559 |
| 20 | 10015005 |
| 21 | 29255655 |
| 22 | 85766655 |
| 23 | 252201690 |
| 24 | 743819115 |
| 25 | 2199446652 |
| 26 | 6519727800 |
| 27 | 19369551936 |
| 28 | 57665571072 |
| 29 | 172011364452 |
| 30 | 514021640564 |
| 31 | 1538650042952 |