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 | 2 |
| 6 | 3 |
| 7 | 7 |
| 8 | 15 |
| 9 | 39 |
| 10 | 107 |
| 11 | 324 |
| 12 | 1072 |
| 13 | 3778 |
| 14 | 14228 |
| 15 | 56568 |
| 16 | 235449 |
| 17 | 1021381 |
| 18 | 4596328 |
| 19 | 21383982 |
| 20 | 102594132 |
| 21 | 506544749 |
| 22 | 2569520447 |
| 23 | 13372902590 |
| 24 | 71322154244 |
| 25 | 389402949706 |