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) |
|---|---|
| 1 | 15 |
| 2 | 225 |
| 3 | 2205 |
| 4 | 15779 |
| 5 | 89380 |
| 6 | 422488 |
| 7 | 1727738 |
| 8 | 6272940 |
| 9 | 20614382 |
| 10 | 62231446 |
| 11 | 174603882 |
| 12 | 459586532 |
| 13 | 1143581612 |
| 14 | 2707062766 |
| 15 | 6128575771 |
| 16 | 13328965295 |
| 17 | 27955737041 |
| 18 | 56730240471 |
| 19 | 111704250407 |
| 20 | 213954477597 |
| 21 | 399506181220 |