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 | 1 |
| 3 | 7 |
| 4 | 25 |
| 5 | 75 |
| 6 | 195 |
| 7 | 468 |
| 8 | 1056 |
| 9 | 2280 |
| 10 | 4755 |
| 11 | 9650 |
| 12 | 19154 |
| 13 | 37328 |
| 14 | 71635 |
| 15 | 135685 |
| 16 | 254125 |
| 17 | 471317 |
| 18 | 866669 |
| 19 | 1581620 |
| 20 | 2866970 |
| 21 | 5165630 |
| 22 | 9256871 |
| 23 | 16507092 |
| 24 | 29304660 |
| 25 | 51812160 |
| 26 | 91264885 |
| 27 | 160207603 |
| 28 | 280340161 |
| 29 | 489117135 |
| 30 | 851054535 |