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 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 5 |
| 5 | 18 |
| 6 | 53 |
| 7 | 138 |
| 8 | 332 |
| 9 | 757 |
| 10 | 1661 |
| 11 | 3546 |
| 12 | 7424 |
| 13 | 15328 |
| 14 | 31336 |
| 15 | 63618 |
| 16 | 128531 |
| 17 | 258811 |
| 18 | 519956 |
| 19 | 1042992 |
| 20 | 2090009 |
| 21 | 4185231 |
| 22 | 8377158 |
| 23 | 16762853 |
| 24 | 33536516 |
| 25 | 67086633 |
| 26 | 134190278 |
| 27 | 268401718 |
| 28 | 536829625 |
| 29 | 1073691505 |
| 30 | 2147422558 |