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 | 0 |
| 1 | 1 |
| 2 | 4 |
| 3 | 11 |
| 4 | 30 |
| 5 | 85 |
| 6 | 244 |
| 7 | 715 |
| 8 | 2118 |
| 9 | 6309 |
| 10 | 18860 |
| 11 | 56475 |
| 12 | 169262 |
| 13 | 507541 |
| 14 | 1522244 |
| 15 | 4566155 |
| 16 | 13697590 |
| 17 | 41091429 |
| 18 | 123272252 |
| 19 | 369813659 |
| 20 | 1109436254 |