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 | 3 |
| 2 | 15 |
| 3 | 64 |
| 4 | 261 |
| 5 | 1032 |
| 6 | 3982 |
| 7 | 15066 |
| 8 | 56094 |
| 9 | 206068 |
| 10 | 748452 |
| 11 | 2691966 |
| 12 | 9600233 |
| 13 | 33982197 |
| 14 | 119495229 |
| 15 | 417724302 |
| 16 | 1452550371 |
| 17 | 5026878774 |
| 18 | 17321417650 |
| 19 | 59450099958 |
| 20 | 203306331429 |
| 21 | 692955932103 |
| 22 | 2354664287943 |
| 23 | 7978488379398 |
| 24 | 26963061909228 |
| 25 | 90897971951727 |