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 | 1 |
| 6 | 4 |
| 7 | 14 |
| 8 | 129 |
| 9 | 1980 |
| 10 | 62611 |
| 11 | 2806490 |
| 12 | 158937213 |
| 13 | 10773251972 |
| 14 | 855658082615 |
| 15 | 78558949838723 |
| 16 | 8251166737356319 |
| 17 | 982806379842257309 |
| 18 | 131756174189661102281 |
| 19 | 19748565896506014747623 |
| 20 | 3289970433888731383271400 |
| 21 | 605948436052375098046655323 |
| 22 | 122796503871896458570959144266 |