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 | 2 |
| 2 | 7 |
| 3 | 28 |
| 4 | 114 |
| 5 | 472 |
| 6 | 1988 |
| 7 | 8480 |
| 8 | 36474 |
| 9 | 157720 |
| 10 | 684404 |
| 11 | 2976994 |
| 12 | 12971206 |
| 13 | 56587676 |
| 14 | 247097170 |
| 15 | 1079749976 |
| 16 | 4720841314 |
| 17 | 20649303934 |
| 18 | 90353041092 |
| 19 | 395459463960 |
| 20 | 1731251197242 |
| 21 | 7580521689750 |
| 22 | 33197447406682 |
| 23 | 145400339328566 |
| 24 | 636901149067534 |
| 25 | 2790082285204966 |