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 | 6 |
| 3 | 41 |
| 4 | 362 |
| 5 | 3542 |
| 6 | 37692 |
| 7 | 424377 |
| 8 | 4990722 |
| 9 | 60704138 |
| 10 | 758665388 |
| 11 | 9694652838 |
| 12 | 126203947828 |
| 13 | 1668947978908 |
| 14 | 22370427181624 |
| 15 | 303383342784729 |
| 16 | 4156846359584754 |
| 17 | 57473870722327874 |
| 18 | 801081711581734764 |
| 19 | 11246487794657694810 |
| 20 | 158920231643036635860 |
| 21 | 2258896576436091238860 |