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 | 2 |
| 1 | 12 |
| 2 | 104 |
| 3 | 1008 |
| 4 | 10272 |
| 5 | 107712 |
| 6 | 1150592 |
| 7 | 12451584 |
| 8 | 136053248 |
| 9 | 1497664512 |
| 10 | 16583583744 |
| 11 | 184511361024 |
| 12 | 2061074178048 |
| 13 | 23100352413696 |
| 14 | 259648659554304 |
| 15 | 2925683135152128 |
| 16 | 33037383972814848 |
| 17 | 373774017998094336 |
| 18 | 4235888981636022272 |
| 19 | 48076611822491271168 |