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) |
|---|---|
| 3 | 1 |
| 4 | 4 |
| 5 | 13 |
| 6 | 44 |
| 7 | 145 |
| 8 | 467 |
| 9 | 1475 |
| 10 | 4588 |
| 11 | 14099 |
| 12 | 42919 |
| 13 | 129685 |
| 14 | 389578 |
| 15 | 1164909 |
| 16 | 3470513 |
| 17 | 10309111 |
| 18 | 30551216 |
| 19 | 90368547 |
| 20 | 266900346 |
| 21 | 787325255 |
| 22 | 2320267136 |
| 23 | 6832609927 |
| 24 | 20108081817 |
| 25 | 59149096985 |
| 26 | 173927024292 |
| 27 | 511290023185 |