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 | 1 |
| 2 | 5 |
| 3 | 13 |
| 4 | 57 |
| 5 | 201 |
| 6 | 861 |
| 7 | 3445 |
| 8 | 14897 |
| 9 | 63313 |
| 10 | 278389 |
| 11 | 1223069 |
| 12 | 5465065 |
| 13 | 24513945 |
| 14 | 111037005 |
| 15 | 505298565 |
| 16 | 2314343265 |
| 17 | 10645982625 |
| 18 | 49202944485 |
| 19 | 228253816365 |
| 20 | 1062783893145 |
| 21 | 4964167491945 |
| 22 | 23256852644925 |
| 23 | 109249893866133 |
| 24 | 514494575459217 |
| 25 | 2428488338526961 |