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 | 4 |
| 7 | 14 |
| 8 | 130 |
| 9 | 1981 |
| 10 | 62616 |
| 11 | 2806508 |
| 12 | 158937367 |
| 13 | 10773254138 |
| 14 | 855658147832 |
| 15 | 78558952717569 |
| 16 | 8251166899386729 |
| 17 | 982806390786806618 |
| 18 | 131756175056777580011 |
| 19 | 19748565975966429686408 |
| 20 | 3289970442222058710279611 |
| 21 | 605948437043760750748781907 |
| 22 | 122796504004669690100342096563 |