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 | 6 |
| 3 | 34 |
| 4 | 116 |
| 5 | 678 |
| 6 | 2438 |
| 7 | 14494 |
| 8 | 53538 |
| 9 | 321590 |
| 10 | 1207186 |
| 11 | 7301142 |
| 12 | 27702096 |
| 13 | 168359754 |
| 14 | 643682106 |
| 15 | 3926147730 |
| 16 | 15096518580 |
| 17 | 92338836390 |
| 18 | 356629256930 |
| 19 | 2186194166950 |
| 20 | 8473375581420 |
| 21 | 52037098259090 |
| 22 | 202271610937570 |
| 23 | 1244063987615130 |
| 24 | 4847394356321770 |
| 25 | 29851422385561898 |