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 | 0 |
| 2 | 1 |
| 3 | 5 |
| 4 | 17 |
| 5 | 50 |
| 6 | 138 |
| 7 | 370 |
| 8 | 979 |
| 9 | 2575 |
| 10 | 6755 |
| 11 | 17700 |
| 12 | 46356 |
| 13 | 121380 |
| 14 | 317797 |
| 15 | 832025 |
| 16 | 2178293 |
| 17 | 5702870 |
| 18 | 14930334 |
| 19 | 39088150 |
| 20 | 102334135 |
| 21 | 267914275 |
| 22 | 701408711 |
| 23 | 1836311880 |
| 24 | 4807526952 |
| 25 | 12586269000 |
| 26 | 32951280073 |
| 27 | 86267571245 |
| 28 | 225851433689 |
| 29 | 591286729850 |