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 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 1 |
| 5 | 1 |
| 6 | 2 |
| 7 | 5 |
| 8 | 11 |
| 9 | 25 |
| 10 | 66 |
| 11 | 172 |
| 12 | 485 |
| 13 | 1446 |
| 14 | 4541 |
| 15 | 15036 |
| 16 | 52496 |
| 17 | 192218 |
| 18 | 737248 |
| 19 | 2952621 |
| 20 | 12313532 |
| 21 | 53336122 |
| 22 | 239380403 |
| 23 | 1110793092 |
| 24 | 5318743428 |
| 25 | 26233496486 |
| 26 | 133074975399 |