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) |
|---|---|
| 4 | 1 |
| 5 | 19 |
| 6 | 220 |
| 7 | 2021 |
| 8 | 16246 |
| 9 | 119914 |
| 10 | 835080 |
| 11 | 5579147 |
| 12 | 36150820 |
| 13 | 228879616 |
| 14 | 1423367610 |
| 15 | 8727874180 |
| 16 | 52919787978 |
| 17 | 317969615146 |
| 18 | 1896431659490 |
| 19 | 11241964305405 |
| 20 | 66305996581006 |
| 21 | 389432443869294 |
| 22 | 2279159225280808 |