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 | 1 |
| 1 | 2 |
| 2 | 16 |
| 3 | 130 |
| 4 | 1093 |
| 5 | 9402 |
| 6 | 82160 |
| 7 | 726206 |
| 8 | 6474541 |
| 9 | 58115146 |
| 10 | 524472448 |
| 11 | 4754293704 |
| 12 | 43257431931 |
| 13 | 394821713910 |
| 14 | 3613377083248 |
| 15 | 33146854168628 |
| 16 | 304692552429413 |
| 17 | 2805871076597738 |
| 18 | 25880523571338272 |
| 19 | 239058748663208600 |
| 20 | 2211058130414688244 |
| 21 | 20474163633488699944 |