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 | 0 |
| 3 | 1 |
| 4 | 1 |
| 5 | 7 |
| 6 | 27 |
| 7 | 128 |
| 8 | 640 |
| 9 | 3351 |
| 10 | 18313 |
| 11 | 103404 |
| 12 | 600538 |
| 13 | 3571717 |
| 14 | 21683185 |
| 15 | 134005373 |
| 16 | 841259885 |
| 17 | 5355078350 |
| 18 | 34512405410 |
| 19 | 224908338137 |
| 20 | 1480420941781 |
| 21 | 9833512593113 |
| 22 | 65860442383487 |
| 23 | 444453988418791 |
| 24 | 3020274890688447 |
| 25 | 20656019108074552 |
| 26 | 142107550142684602 |