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 | 1 |
| 2 | 39 |
| 3 | 495 |
| 4 | 3705 |
| 5 | 19995 |
| 6 | 85917 |
| 7 | 311493 |
| 8 | 989235 |
| 9 | 2823990 |
| 10 | 7383610 |
| 11 | 17931498 |
| 12 | 40889862 |
| 13 | 88304970 |
| 14 | 181852230 |
| 15 | 359140470 |
| 16 | 683363994 |
| 17 | 1257722271 |
| 18 | 2246496825 |
| 19 | 3905261425 |
| 20 | 6623425575 |
| 21 | 10983195405 |
| 22 | 17840105595 |
| 23 | 28431558675 |
| 24 | 44521334325 |
| 25 | 68589834300 |
| 26 | 104081944356 |