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 | 5 |
| 3 | 20 |
| 4 | 80 |
| 5 | 325 |
| 6 | 1326 |
| 7 | 5411 |
| 8 | 22076 |
| 9 | 90061 |
| 10 | 367411 |
| 11 | 1498887 |
| 12 | 6114853 |
| 13 | 24946129 |
| 14 | 101770120 |
| 15 | 415180936 |
| 16 | 1693770328 |
| 17 | 6909898016 |
| 18 | 28189589705 |
| 19 | 115002126790 |
| 20 | 469162173146 |
| 21 | 1913991948274 |
| 22 | 7808313175575 |
| 23 | 31854760257925 |
| 24 | 129954540535600 |
| 25 | 530161974821876 |