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 | 0 |
| 1 | 0 |
| 2 | 0 |
| 3 | 2 |
| 4 | 47 |
| 5 | 671 |
| 6 | 8491 |
| 7 | 101787 |
| 8 | 1180751 |
| 9 | 13377156 |
| 10 | 148930536 |
| 11 | 1636170477 |
| 12 | 17787688377 |
| 13 | 191742524399 |
| 14 | 2052389350029 |
| 15 | 21838745177567 |
| 16 | 231206458686127 |
| 17 | 2437121982958248 |
| 18 | 25591920108631224 |
| 19 | 267840642082525459 |