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 | 1 |
| 2 | 11 |
| 3 | 105 |
| 4 | 919 |
| 5 | 7713 |
| 6 | 63351 |
| 7 | 514321 |
| 8 | 4148839 |
| 9 | 33347041 |
| 10 | 267489431 |
| 11 | 2143168305 |
| 12 | 17160184519 |
| 13 | 137349160833 |
| 14 | 1099102033911 |
| 15 | 8794224638161 |
| 16 | 70360221445159 |
| 17 | 562911076526881 |
| 18 | 4503422288363351 |
| 19 | 36027988077717105 |
| 20 | 288226686123491719 |
| 21 | 2305826176955087553 |
| 22 | 18446667292472959671 |