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 | 1 |
| 1 | 0 |
| 2 | 6 |
| 3 | 6 |
| 4 | 30 |
| 5 | 60 |
| 6 | 170 |
| 7 | 420 |
| 8 | 1050 |
| 9 | 2660 |
| 10 | 6552 |
| 11 | 16380 |
| 12 | 40362 |
| 13 | 99792 |
| 14 | 245520 |
| 15 | 603372 |
| 16 | 1480050 |
| 17 | 3624192 |
| 18 | 8863712 |
| 19 | 21647340 |
| 20 | 52811616 |
| 21 | 128700000 |
| 22 | 313341756 |
| 23 | 762206016 |
| 24 | 1852565650 |
| 25 | 4499346072 |
| 26 | 10919990460 |
| 27 | 26485897932 |
| 28 | 64201490352 |
| 29 | 155536089240 |
| 30 | 376606931436 |