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 | 4 |
| 2 | 25 |
| 3 | 98 |
| 4 | 386 |
| 5 | 1402 |
| 6 | 4938 |
| 7 | 16936 |
| 8 | 57020 |
| 9 | 189172 |
| 10 | 620397 |
| 11 | 2015456 |
| 12 | 6496391 |
| 13 | 20801576 |
| 14 | 66231279 |
| 15 | 209847980 |
| 16 | 662049349 |
| 17 | 2080850248 |
| 18 | 6518383898 |
| 19 | 20358327362 |
| 20 | 63413001935 |
| 21 | 197042859318 |
| 22 | 610922240964 |
| 23 | 1890331512546 |
| 24 | 5838350817615 |
| 25 | 18001432735438 |
| 26 | 55417333344241 |