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 | 3 |
| 3 | 9 |
| 4 | 22 |
| 5 | 54 |
| 6 | 136 |
| 7 | 340 |
| 8 | 857 |
| 9 | 2164 |
| 10 | 5481 |
| 11 | 13911 |
| 12 | 35379 |
| 13 | 90124 |
| 14 | 229913 |
| 15 | 587254 |
| 16 | 1501615 |
| 17 | 3843314 |
| 18 | 9845118 |
| 19 | 25238541 |
| 20 | 64744455 |
| 21 | 166190960 |
| 22 | 426829202 |
| 23 | 1096784835 |
| 24 | 2819620836 |
| 25 | 7251796132 |
| 26 | 18658280277 |
| 27 | 48023738374 |
| 28 | 123648031266 |
| 29 | 318460151301 |
| 30 | 820446813941 |