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 | 10 |
| 3 | 60 |
| 4 | 364 |
| 5 | 2745 |
| 6 | 27246 |
| 7 | 346864 |
| 8 | 5422264 |
| 9 | 100449225 |
| 10 | 2149062490 |
| 11 | 52097910876 |
| 12 | 1410401518692 |
| 13 | 42153624499441 |
| 14 | 1378058477508454 |
| 15 | 48900582823143360 |
| 16 | 1871456346915007216 |
| 17 | 76821658841556480753 |
| 18 | 3366451935514051046802 |
| 19 | 156839738363103277783900 |