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 | 0 |
| 3 | 102 |
| 4 | 250 |
| 5 | 5253 |
| 6 | 16478 |
| 7 | 278315 |
| 8 | 1019120 |
| 9 | 15188955 |
| 10 | 62846854 |
| 11 | 850526529 |
| 12 | 3891052774 |
| 13 | 48586797398 |
| 14 | 241642747938 |
| 15 | 2818541243728 |
| 16 | 15034216343154 |
| 17 | 165507316465985 |
| 18 | 936470483789652 |
| 19 | 9815405179117090 |
| 20 | 58379693308010828 |