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 | 53 |
| 2 | 1378 |
| 3 | 23426 |
| 4 | 292825 |
| 5 | 2869685 |
| 6 | 22957480 |
| 7 | 154143080 |
| 8 | 886322710 |
| 9 | 4431613550 |
| 10 | 19499099620 |
| 11 | 76223753060 |
| 12 | 266783135710 |
| 13 | 841392966470 |
| 14 | 2403979904200 |
| 15 | 6250347750920 |
| 16 | 14844575908435 |
| 17 | 32308782859535 |
| 18 | 64617565719070 |
| 19 | 119032357903550 |
| 20 | 202355008436035 |