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 | 0 |
| 2 | 1 |
| 3 | 2 |
| 4 | 5 |
| 5 | 10 |
| 6 | 27 |
| 7 | 62 |
| 8 | 165 |
| 9 | 423 |
| 10 | 1140 |
| 11 | 3060 |
| 12 | 8427 |
| 13 | 23218 |
| 14 | 64782 |
| 15 | 181370 |
| 16 | 511004 |
| 17 | 1444285 |
| 18 | 4097996 |
| 19 | 11656644 |
| 20 | 33243265 |
| 21 | 94992847 |
| 22 | 271953126 |
| 23 | 779790166 |
| 24 | 2239187466 |
| 25 | 6438039076 |
| 26 | 18532004323 |
| 27 | 53400606823 |
| 28 | 154024168401 |
| 29 | 444646510812 |
| 30 | 1284682242777 |