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 | 30 |
| 3 | 240 |
| 4 | 1020 |
| 5 | 3120 |
| 6 | 7770 |
| 7 | 16800 |
| 8 | 32760 |
| 9 | 59040 |
| 10 | 99990 |
| 11 | 161040 |
| 12 | 248820 |
| 13 | 371280 |
| 14 | 537810 |
| 15 | 759360 |
| 16 | 1048560 |
| 17 | 1419840 |
| 18 | 1889550 |
| 19 | 2476080 |
| 20 | 3199980 |
| 21 | 4084080 |
| 22 | 5153610 |
| 23 | 6436320 |
| 24 | 7962600 |
| 25 | 9765600 |
| 26 | 11881350 |
| 27 | 14348880 |
| 28 | 17210340 |
| 29 | 20511120 |
| 30 | 24299970 |
| 31 | 28629120 |