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 | 1 |
| 2 | 2 |
| 3 | 5 |
| 4 | 15 |
| 5 | 49 |
| 6 | 166 |
| 7 | 577 |
| 8 | 2050 |
| 9 | 7414 |
| 10 | 27201 |
| 11 | 100984 |
| 12 | 378651 |
| 13 | 1431901 |
| 14 | 5454718 |
| 15 | 20912754 |
| 16 | 80630085 |
| 17 | 312430832 |
| 18 | 1216045522 |
| 19 | 4752132953 |
| 20 | 18638125275 |
| 21 | 73340870891 |
| 22 | 289463959745 |
| 23 | 1145612705905 |
| 24 | 4545478673125 |
| 25 | 18077348646721 |
| 26 | 72048928923617 |
| 27 | 287733587217552 |
| 28 | 1151233484320195 |