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 | 5 |
| 2 | 20 |
| 3 | 67 |
| 4 | 209 |
| 5 | 630 |
| 6 | 1873 |
| 7 | 5540 |
| 8 | 16357 |
| 9 | 48265 |
| 10 | 142387 |
| 11 | 420027 |
| 12 | 1239006 |
| 13 | 3654820 |
| 14 | 10780958 |
| 15 | 31801551 |
| 16 | 93807834 |
| 17 | 276713194 |
| 18 | 816245143 |
| 19 | 2407749755 |
| 20 | 7102350204 |
| 21 | 20950424039 |
| 22 | 61799299470 |
| 23 | 182294802589 |
| 24 | 537730934397 |