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 | 0 |
| 2 | 1 |
| 3 | 2 |
| 4 | 5 |
| 5 | 11 |
| 6 | 28 |
| 7 | 67 |
| 8 | 171 |
| 9 | 433 |
| 10 | 1123 |
| 11 | 2924 |
| 12 | 7720 |
| 13 | 20487 |
| 14 | 54838 |
| 15 | 147570 |
| 16 | 399466 |
| 17 | 1086312 |
| 18 | 2967517 |
| 19 | 8137552 |
| 20 | 22395604 |
| 21 | 61833349 |
| 22 | 171227674 |
| 23 | 475442129 |
| 24 | 1323449661 |
| 25 | 3692461865 |
| 26 | 10324097819 |
| 27 | 28923331940 |
| 28 | 81179488039 |
| 29 | 228240293289 |
| 30 | 642744665401 |
| 31 | 1812762839702 |