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 | 34 |
| 3 | 345 |
| 4 | 2404 |
| 5 | 15145 |
| 6 | 98646 |
| 7 | 707329 |
| 8 | 5691400 |
| 9 | 51281649 |
| 10 | 512916490 |
| 11 | 5642242441 |
| 12 | 67707158124 |
| 13 | 880193426905 |
| 14 | 12322708514494 |
| 15 | 184840628476785 |
| 16 | 2957450056677136 |
| 17 | 50276650964931169 |
| 18 | 904979717370650610 |
| 19 | 17194614630044837689 |
| 20 | 343892292600899953780 |