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 | 0 |
| 3 | 1 |
| 4 | 5 |
| 5 | 18 |
| 6 | 56 |
| 7 | 160 |
| 8 | 432 |
| 9 | 1121 |
| 10 | 2827 |
| 11 | 6988 |
| 12 | 17052 |
| 13 | 41334 |
| 14 | 100082 |
| 15 | 243205 |
| 16 | 595313 |
| 17 | 1471278 |
| 18 | 3674756 |
| 19 | 9272410 |
| 20 | 23605202 |
| 21 | 60513201 |
| 22 | 155893167 |
| 23 | 402819550 |
| 24 | 1042358942 |
| 25 | 2697994240 |
| 26 | 6979913196 |
| 27 | 18041181065 |
| 28 | 46583002021 |
| 29 | 120161923640 |
| 30 | 309719942306 |