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 | 6 |
| 2 | 20 |
| 3 | 56 |
| 4 | 140 |
| 5 | 330 |
| 6 | 745 |
| 7 | 1634 |
| 8 | 3504 |
| 9 | 7388 |
| 10 | 15366 |
| 11 | 31612 |
| 12 | 64446 |
| 13 | 130391 |
| 14 | 262113 |
| 15 | 523984 |
| 16 | 1042433 |
| 17 | 2065098 |
| 18 | 4075761 |
| 19 | 8017395 |
| 20 | 15724110 |
| 21 | 30756544 |
| 22 | 60014931 |
| 23 | 116849951 |
| 24 | 227054267 |
| 25 | 440389499 |
| 26 | 852738289 |
| 27 | 1648633351 |
| 28 | 3182830233 |