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 | 2 |
| 2 | 8 |
| 3 | 44 |
| 4 | 310 |
| 5 | 2606 |
| 6 | 25202 |
| 7 | 272582 |
| 8 | 3233738 |
| 9 | 41454272 |
| 10 | 567709144 |
| 11 | 8230728508 |
| 12 | 125413517530 |
| 13 | 1996446632130 |
| 14 | 33039704641922 |
| 15 | 566087847780250 |
| 16 | 10006446665899330 |
| 17 | 181938461947322284 |
| 18 | 3393890553702212368 |
| 19 | 64807885247524512668 |
| 20 | 1264344439859632559216 |