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) |
|---|---|
| 2 | 2 |
| 3 | 15 |
| 4 | 100 |
| 5 | 757 |
| 6 | 5902 |
| 7 | 46907 |
| 8 | 377520 |
| 9 | 3065809 |
| 10 | 25078650 |
| 11 | 206416795 |
| 12 | 1708129244 |
| 13 | 14202265321 |
| 14 | 118585167502 |
| 15 | 993915161547 |
| 16 | 8358970631568 |
| 17 | 70518298143329 |
| 18 | 596590060985546 |
| 19 | 5060232622624651 |
| 20 | 43022268222676124 |
| 21 | 366575545244139845 |
| 22 | 3129747701356459022 |
| 23 | 26771150349554898415 |