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 | 23 |
| 2 | 144 |
| 3 | 848 |
| 4 | 4880 |
| 5 | 27816 |
| 6 | 157920 |
| 7 | 895264 |
| 8 | 5074272 |
| 9 | 28772280 |
| 10 | 163262704 |
| 11 | 927203184 |
| 12 | 5270629104 |
| 13 | 29988361032 |
| 14 | 170780080320 |
| 15 | 973422085184 |
| 16 | 5552990609344 |
| 17 | 31702646247768 |
| 18 | 181128948471888 |
| 19 | 1035584204252560 |