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 | 0 |
| 1 | 1 |
| 2 | 7 |
| 3 | 31 |
| 4 | 115 |
| 5 | 391 |
| 6 | 1267 |
| 7 | 3991 |
| 8 | 12355 |
| 9 | 37831 |
| 10 | 115027 |
| 11 | 348151 |
| 12 | 1050595 |
| 13 | 3164071 |
| 14 | 9516787 |
| 15 | 28599511 |
| 16 | 85896835 |
| 17 | 257887111 |
| 18 | 774054547 |
| 19 | 2322950071 |
| 20 | 6970423075 |
| 21 | 20914414951 |
| 22 | 62749536307 |
| 23 | 188261191831 |
| 24 | 564808741315 |
| 25 | 1694476555591 |