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 | 5 |
| 2 | 29 |
| 3 | 165 |
| 4 | 1020 |
| 5 | 6606 |
| 6 | 44805 |
| 7 | 314299 |
| 8 | 2266834 |
| 9 | 16714004 |
| 10 | 125501364 |
| 11 | 956725836 |
| 12 | 7387322749 |
| 13 | 57669478609 |
| 14 | 454492588153 |
| 15 | 3611698593169 |
| 16 | 28911762536992 |
| 17 | 232949503809562 |
| 18 | 1887883708627582 |
| 19 | 15380196764853214 |
| 20 | 125893997550676627 |
| 21 | 1034945699861044243 |