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 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 10 |
| 5 | 26 |
| 6 | 76 |
| 7 | 232 |
| 8 | 764 |
| 9 | 2620 |
| 10 | 9496 |
| 11 | 35696 |
| 12 | 130656 |
| 13 | 464036 |
| 14 | 1615276 |
| 15 | 5517828 |
| 16 | 18628384 |
| 17 | 62330046 |
| 18 | 207657610 |
| 19 | 690610926 |
| 20 | 2299356168 |
| 21 | 7678084407 |
| 22 | 25759043565 |
| 23 | 86697055428 |
| 24 | 292427968880 |
| 25 | 987581324508 |
| 26 | 3337168641756 |
| 27 | 11277361448224 |
| 28 | 38099089805120 |