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 | 28 |
| 3 | 140 |
| 4 | 496 |
| 5 | 2970 |
| 6 | 8128 |
| 7 | 27846 |
| 8 | 105664 |
| 9 | 117800 |
| 10 | 237510 |
| 11 | 539400 |
| 12 | 1421280 |
| 13 | 1539720 |
| 14 | 2290260 |
| 15 | 4358600 |
| 16 | 8872200 |
| 17 | 33550336 |
| 18 | 50401728 |
| 19 | 90409410 |
| 20 | 233103780 |
| 21 | 287425800 |
| 22 | 318177800 |
| 23 | 423184320 |
| 24 | 559903400 |
| 25 | 825120800 |
| 26 | 1632825792 |
| 27 | 2705020500 |
| 28 | 3209343200 |
| 29 | 3328809120 |
| 30 | 4720896180 |