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 | 16 |
| 3 | 62 |
| 4 | 230 |
| 5 | 812 |
| 6 | 2728 |
| 7 | 8752 |
| 8 | 26944 |
| 9 | 80000 |
| 10 | 230144 |
| 11 | 644096 |
| 12 | 1759744 |
| 13 | 4707328 |
| 14 | 12359680 |
| 15 | 31920128 |
| 16 | 81231872 |
| 17 | 204013568 |
| 18 | 506331136 |
| 19 | 1243217920 |
| 20 | 3022913536 |
| 21 | 7285243904 |
| 22 | 17415274496 |
| 23 | 41321234432 |
| 24 | 97370767360 |
| 25 | 227993976832 |
| 26 | 530713673728 |