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 | 9 |
| 2 | 48 |
| 3 | 198 |
| 4 | 699 |
| 5 | 2223 |
| 6 | 6562 |
| 7 | 18324 |
| 8 | 49029 |
| 9 | 126837 |
| 10 | 319332 |
| 11 | 786258 |
| 12 | 1900351 |
| 13 | 4521771 |
| 14 | 10616598 |
| 15 | 24641280 |
| 16 | 56622825 |
| 17 | 128974545 |
| 18 | 291503800 |
| 19 | 654311070 |
| 20 | 1459617411 |
| 21 | 3238002279 |
| 22 | 7147093578 |
| 23 | 15703473708 |
| 24 | 34359737869 |
| 25 | 74893491693 |