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) |
|---|---|
| 1 | 1 |
| 2 | 15 |
| 3 | 126 |
| 4 | 700 |
| 5 | 2850 |
| 6 | 9261 |
| 7 | 25480 |
| 8 | 61776 |
| 9 | 135675 |
| 10 | 275275 |
| 11 | 523446 |
| 12 | 943020 |
| 13 | 1623076 |
| 14 | 2686425 |
| 15 | 4298400 |
| 16 | 6677056 |
| 17 | 10104885 |
| 18 | 14942151 |
| 19 | 21641950 |
| 20 | 30767100 |
| 21 | 43008966 |
| 22 | 59208325 |
| 23 | 80378376 |
| 24 | 107730000 |
| 25 | 142699375 |
| 26 | 186978051 |
| 27 | 242545590 |