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 | 0 |
| 1 | 1 |
| 2 | 3 |
| 3 | 9 |
| 4 | 30 |
| 5 | 112 |
| 6 | 463 |
| 7 | 2095 |
| 8 | 10279 |
| 9 | 54267 |
| 10 | 306298 |
| 11 | 1838320 |
| 12 | 11677867 |
| 13 | 78207601 |
| 14 | 550277003 |
| 15 | 4055549053 |
| 16 | 31224520322 |
| 17 | 250547144156 |
| 18 | 2090779592827 |
| 19 | 18110124715919 |
| 20 | 162546260131455 |
| 21 | 1509352980864191 |
| 22 | 14478981877739094 |
| 23 | 143299752100925452 |
| 24 | 1461455003961745247 |