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 | 10 |
| 3 | 62 |
| 4 | 370 |
| 5 | 2102 |
| 6 | 11530 |
| 7 | 61742 |
| 8 | 325090 |
| 9 | 1690982 |
| 10 | 8717050 |
| 11 | 44633822 |
| 12 | 227363410 |
| 13 | 1153594262 |
| 14 | 5835080170 |
| 15 | 29443836302 |
| 16 | 148292923330 |
| 17 | 745759583942 |
| 18 | 3745977788890 |
| 19 | 18798608421182 |
| 20 | 94267920012850 |
| 21 | 472439111692022 |