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 | 0 |
| 4 | 0 |
| 5 | 0 |
| 6 | 1 |
| 7 | 18 |
| 8 | 261 |
| 9 | 3420 |
| 10 | 42300 |
| 11 | 504000 |
| 12 | 5850000 |
| 13 | 66599991 |
| 14 | 746999757 |
| 15 | 8279995383 |
| 16 | 90899925399 |
| 17 | 989998904070 |
| 18 | 10709984885400 |
| 19 | 115199800740000 |
| 20 | 1232997460650081 |
| 21 | 13139968482902916 |
| 22 | 139499617032068526 |
| 23 | 1475995426741315116 |
| 24 | 15569946175522343121 |