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 | 1 |
| 2 | 9 |
| 3 | 52 |
| 4 | 413 |
| 5 | 3916 |
| 6 | 41077 |
| 7 | 481384 |
| 8 | 6198425 |
| 9 | 86430160 |
| 10 | 1296040841 |
| 11 | 20763245944 |
| 12 | 353272341061 |
| 13 | 6353672109760 |
| 14 | 120315348389069 |
| 15 | 2390488408994536 |
| 16 | 49682962883210033 |
| 17 | 1077292416660660736 |
| 18 | 24313317132393295633 |
| 19 | 569937590287796925784 |
| 20 | 13850459183086300341341 |