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) |
|---|---|
| 1 | 0 |
| 2 | 1 |
| 3 | 4 |
| 4 | 13 |
| 5 | 43 |
| 6 | 132 |
| 7 | 400 |
| 8 | 1184 |
| 9 | 3461 |
| 10 | 9999 |
| 11 | 28634 |
| 12 | 81383 |
| 13 | 229860 |
| 14 | 645731 |
| 15 | 1805582 |
| 16 | 5028189 |
| 17 | 13952221 |
| 18 | 38590922 |
| 19 | 106434540 |
| 20 | 292792026 |
| 21 | 803565215 |
| 22 | 2200694791 |
| 23 | 6015268164 |
| 24 | 16412564173 |
| 25 | 44708036568 |
| 26 | 121600924117 |
| 27 | 330277253560 |