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 | 5 |
| 3 | 22 |
| 4 | 99 |
| 5 | 471 |
| 6 | 2386 |
| 7 | 12867 |
| 8 | 73681 |
| 9 | 446620 |
| 10 | 2856457 |
| 11 | 19217243 |
| 12 | 135610448 |
| 13 | 1001159901 |
| 14 | 7714225057 |
| 15 | 61904585510 |
| 16 | 516347066551 |
| 17 | 4468588592739 |
| 18 | 40058673825258 |
| 19 | 371421499686007 |
| 20 | 3556976106133821 |
| 21 | 35138574378189700 |
| 22 | 357654857584636597 |
| 23 | 3746672593640388775 |