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 | 4 |
| 3 | 9 |
| 4 | 22 |
| 5 | 57 |
| 6 | 153 |
| 7 | 420 |
| 8 | 1170 |
| 9 | 3293 |
| 10 | 9339 |
| 11 | 26642 |
| 12 | 76363 |
| 13 | 219728 |
| 14 | 634312 |
| 15 | 1836229 |
| 16 | 5328346 |
| 17 | 15494125 |
| 18 | 45137995 |
| 19 | 131712826 |
| 20 | 384900937 |
| 21 | 1126265986 |
| 22 | 3299509114 |
| 23 | 9676690939 |
| 24 | 28407473191 |
| 25 | 83470059532 |
| 26 | 245465090758 |
| 27 | 722406781935 |
| 28 | 2127562036990 |
| 29 | 6270020029353 |