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 | 6 |
| 2 | 0 |
| 3 | 30 |
| 4 | 30 |
| 5 | 210 |
| 6 | 180 |
| 7 | 1290 |
| 8 | 1260 |
| 9 | 7740 |
| 10 | 7560 |
| 11 | 46650 |
| 12 | 46410 |
| 13 | 279930 |
| 14 | 278640 |
| 15 | 1679370 |
| 16 | 1678320 |
| 17 | 10077690 |
| 18 | 10069740 |
| 19 | 60466170 |
| 20 | 60458370 |
| 21 | 362795730 |
| 22 | 362750400 |
| 23 | 2176782330 |
| 24 | 2176734420 |
| 25 | 13060693800 |
| 26 | 13060414080 |
| 27 | 78364156320 |
| 28 | 78363884130 |
| 29 | 470184984570 |
| 30 | 470183297220 |