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 | 21 |
| 2 | 210 |
| 3 | 1386 |
| 4 | 6930 |
| 5 | 28314 |
| 6 | 99099 |
| 7 | 306735 |
| 8 | 858858 |
| 9 | 2212210 |
| 10 | 5309304 |
| 11 | 11992344 |
| 12 | 25697880 |
| 13 | 52581816 |
| 14 | 103285710 |
| 15 | 195635286 |
| 16 | 358664691 |
| 17 | 638489775 |
| 18 | 1106715610 |
| 19 | 1872263250 |
| 20 | 3097744650 |
| 21 | 5021809650 |
| 22 | 7989242625 |
| 23 | 12491007165 |
| 24 | 19216934100 |
| 25 | 29124331236 |
| 26 | 43526473056 |