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) |
|---|---|
| 3 | 1 |
| 4 | 5 |
| 5 | 23 |
| 6 | 99 |
| 7 | 413 |
| 8 | 1691 |
| 9 | 6842 |
| 10 | 27464 |
| 11 | 109631 |
| 12 | 435887 |
| 13 | 1728018 |
| 14 | 6835668 |
| 15 | 26996393 |
| 16 | 106486529 |
| 17 | 419639903 |
| 18 | 1652533719 |
| 19 | 6504159137 |
| 20 | 25589302163 |
| 21 | 100646529977 |
| 22 | 395775842389 |
| 23 | 1556107102849 |
| 24 | 6117771240251 |
| 25 | 24050813530815 |
| 26 | 94550689834203 |
| 27 | 371715533473021 |
| 28 | 1461430355605367 |
| 29 | 5746128800657639 |
| 30 | 22594839306797223 |