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 | 1 |
| 4 | 4 |
| 5 | 18 |
| 6 | 106 |
| 7 | 842 |
| 8 | 11094 |
| 9 | 261033 |
| 10 | 11716465 |
| 11 | 1006700330 |
| 12 | 164059829925 |
| 13 | 50335907867918 |
| 14 | 29003487462844902 |
| 15 | 31397381142761234219 |
| 16 | 63969560113225176156957 |
| 17 | 245871831682084026519479939 |
| 18 | 1787331725248899088890200452713 |
| 19 | 24636021429399867655322650759363689 |