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 | 2 |
| 2 | 9 |
| 3 | 37 |
| 4 | 151 |
| 5 | 616 |
| 6 | 2513 |
| 7 | 10252 |
| 8 | 41824 |
| 9 | 170625 |
| 10 | 696081 |
| 11 | 2839729 |
| 12 | 11584946 |
| 13 | 47261895 |
| 14 | 192809420 |
| 15 | 786584466 |
| 16 | 3208946545 |
| 17 | 13091204281 |
| 18 | 53406819691 |
| 19 | 217878227876 |
| 20 | 888855064897 |
| 21 | 3626169232672 |
| 22 | 14793304131648 |
| 23 | 60350698792449 |
| 24 | 246206446668325 |
| 25 | 1004422742303477 |