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 | 9 |
| 3 | 28 |
| 4 | 88 |
| 5 | 270 |
| 6 | 808 |
| 7 | 2386 |
| 8 | 6960 |
| 9 | 20104 |
| 10 | 57607 |
| 11 | 163950 |
| 12 | 463907 |
| 13 | 1306104 |
| 14 | 3661248 |
| 15 | 10223820 |
| 16 | 28452400 |
| 17 | 78941412 |
| 18 | 218426608 |
| 19 | 602886704 |
| 20 | 1660329597 |
| 21 | 4563175466 |
| 22 | 12517834605 |
| 23 | 34280427828 |
| 24 | 93729509848 |
| 25 | 255900484218 |
| 26 | 697712467704 |
| 27 | 1899912606358 |
| 28 | 5167488465184 |