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 | 4 |
| 2 | 14 |
| 3 | 54 |
| 4 | 185 |
| 5 | 619 |
| 6 | 2027 |
| 7 | 6553 |
| 8 | 21044 |
| 9 | 67231 |
| 10 | 214122 |
| 11 | 680330 |
| 12 | 2158391 |
| 13 | 6840384 |
| 14 | 21663503 |
| 15 | 68575557 |
| 16 | 217004842 |
| 17 | 686552743 |
| 18 | 2171766332 |
| 19 | 6869227848 |
| 20 | 21725636644 |
| 21 | 68709456167 |
| 22 | 217293374285 |
| 23 | 687174291753 |
| 24 | 2173105517385 |
| 25 | 6872112993377 |
| 26 | 21731852479862 |
| 27 | 68722847672629 |
| 28 | 217322225558934 |
| 29 | 687236449779456 |
| 30 | 2173239433013146 |