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 | 4 |
| 3 | 21 |
| 4 | 30 |
| 5 | 11 |
| 6 | 80 |
| 7 | 622 |
| 8 | 2055 |
| 9 | 4584 |
| 10 | 10711 |
| 11 | 34354 |
| 12 | 115480 |
| 13 | 341213 |
| 14 | 934750 |
| 15 | 2640483 |
| 16 | 7874188 |
| 17 | 23564242 |
| 18 | 68738591 |
| 19 | 198108496 |
| 20 | 575654335 |
| 21 | 1688669686 |
| 22 | 4951141372 |
| 23 | 14443935957 |
| 24 | 42064267934 |
| 25 | 122731975243 |
| 26 | 358682023576 |
| 27 | 1047906654118 |
| 28 | 3058580566407 |