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) |
|---|---|
| 4 | 21 |
| 5 | 483 |
| 6 | 6468 |
| 7 | 66066 |
| 8 | 570570 |
| 9 | 4390386 |
| 10 | 31039008 |
| 11 | 205633428 |
| 12 | 1293938646 |
| 13 | 7808250450 |
| 14 | 45510945480 |
| 15 | 257611421340 |
| 16 | 1422156202740 |
| 17 | 7683009544980 |
| 18 | 40729207226400 |
| 19 | 212347275857640 |
| 20 | 1090848505817070 |
| 21 | 5530195966465170 |
| 22 | 27704671055301240 |
| 23 | 137308238124957900 |
| 24 | 673903972248687180 |