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 | 4 |
| 2 | 9 |
| 3 | 24 |
| 4 | 71 |
| 5 | 224 |
| 6 | 740 |
| 7 | 2496 |
| 8 | 8565 |
| 9 | 29792 |
| 10 | 104701 |
| 11 | 371304 |
| 12 | 1326702 |
| 13 | 4771380 |
| 14 | 17256161 |
| 15 | 62712800 |
| 16 | 228883359 |
| 17 | 838492436 |
| 18 | 3081972336 |
| 19 | 11361867384 |
| 20 | 41998361480 |
| 21 | 155620033360 |
| 22 | 577900838281 |