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 | 90 |
| 4 | 630 |
| 5 | 2520 |
| 6 | 7560 |
| 7 | 18900 |
| 8 | 41580 |
| 9 | 83160 |
| 10 | 154440 |
| 11 | 270270 |
| 12 | 450450 |
| 13 | 720720 |
| 14 | 1113840 |
| 15 | 1670760 |
| 16 | 2441880 |
| 17 | 3488400 |
| 18 | 4883760 |
| 19 | 6715170 |
| 20 | 9085230 |
| 21 | 12113640 |
| 22 | 15939000 |
| 23 | 20720700 |
| 24 | 26640900 |
| 25 | 33906600 |
| 26 | 42751800 |
| 27 | 53439750 |
| 28 | 66265290 |
| 29 | 81557280 |
| 30 | 99681120 |
| 31 | 121041360 |
| 32 | 146084400 |