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 | 6 |
| 3 | 18 |
| 4 | 52 |
| 5 | 130 |
| 6 | 310 |
| 7 | 718 |
| 8 | 1618 |
| 9 | 3670 |
| 10 | 8160 |
| 11 | 17862 |
| 12 | 38872 |
| 13 | 84016 |
| 14 | 180502 |
| 15 | 386092 |
| 16 | 821640 |
| 17 | 1742536 |
| 18 | 3681130 |
| 19 | 7754076 |
| 20 | 16290046 |
| 21 | 34136028 |
| 22 | 71378568 |
| 23 | 148948138 |
| 24 | 310248240 |
| 25 | 645155196 |
| 26 | 1339484196 |
| 27 | 2777105128 |
| 28 | 5750079046 |
| 29 | 11891268400 |
| 30 | 24563311308 |
| 31 | 50685770166 |
| 32 | 104484802056 |