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 | 4 |
| 2 | 10 |
| 3 | 32 |
| 4 | 137 |
| 5 | 766 |
| 6 | 5382 |
| 7 | 46022 |
| 8 | 467206 |
| 9 | 5519252 |
| 10 | 74629263 |
| 11 | 1139283601 |
| 12 | 19411643752 |
| 13 | 365595475542 |
| 14 | 7548810986515 |
| 15 | 169681672611815 |
| 16 | 4126880020198630 |
| 17 | 108026180912533227 |
| 18 | 3029184083924476085 |
| 19 | 90617948406514693702 |
| 20 | 2881333799993441893564 |
| 21 | 97057552263114611503090 |