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 | 3 |
| 3 | 2 |
| 4 | 3 |
| 5 | 6 |
| 6 | 14 |
| 7 | 36 |
| 8 | 102 |
| 9 | 306 |
| 10 | 972 |
| 11 | 3216 |
| 12 | 11050 |
| 13 | 39138 |
| 14 | 142446 |
| 15 | 530656 |
| 16 | 2018352 |
| 17 | 7818864 |
| 18 | 30792396 |
| 19 | 123075000 |
| 20 | 498564768 |
| 21 | 2044416718 |
| 22 | 8477328954 |
| 23 | 35513219388 |
| 24 | 150179868736 |
| 25 | 640638311244 |
| 26 | 2754973241580 |
| 27 | 11936532238388 |
| 28 | 52080345520680 |
| 29 | 228720427370874 |
| 30 | 1010627725860522 |