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 | 4 |
| 1 | 33 |
| 2 | 153 |
| 3 | 525 |
| 4 | 1485 |
| 5 | 3663 |
| 6 | 8151 |
| 7 | 16731 |
| 8 | 32175 |
| 9 | 58630 |
| 10 | 102102 |
| 11 | 171054 |
| 12 | 277134 |
| 13 | 436050 |
| 14 | 668610 |
| 15 | 1001946 |
| 16 | 1470942 |
| 17 | 2119887 |
| 18 | 3004375 |
| 19 | 4193475 |
| 20 | 5772195 |
| 21 | 7844265 |
| 22 | 10535265 |
| 23 | 13996125 |
| 24 | 18407025 |
| 25 | 23981724 |
| 26 | 30972348 |
| 27 | 39674668 |
| 28 | 50433900 |