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 | 23 |
| 5 | 515 |
| 6 | 10210 |
| 7 | 221130 |
| 8 | 5499165 |
| 9 | 158416629 |
| 10 | 5264924490 |
| 11 | 200122583760 |
| 12 | 8616774658305 |
| 13 | 416417619554365 |
| 14 | 22400104990385122 |
| 15 | 1331442091500919580 |
| 16 | 86886850043131597095 |
| 17 | 6189883012226095338135 |
| 18 | 478992622411196645778030 |