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 | 1 |
| 2 | 21 |
| 3 | 41 |
| 4 | 461 |
| 5 | 1281 |
| 6 | 10501 |
| 7 | 36121 |
| 8 | 246141 |
| 9 | 968561 |
| 10 | 5891381 |
| 11 | 25262601 |
| 12 | 143090221 |
| 13 | 648342241 |
| 14 | 3510146661 |
| 15 | 16476991481 |
| 16 | 86679924701 |
| 17 | 416219754321 |
| 18 | 2149818248341 |
| 19 | 10474213334761 |
| 20 | 53470578301581 |
| 21 | 262954844996801 |