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 | 1 |
| 3 | 4 |
| 4 | 11 |
| 5 | 49 |
| 6 | 204 |
| 7 | 984 |
| 8 | 4807 |
| 9 | 24739 |
| 10 | 130065 |
| 11 | 701584 |
| 12 | 3851316 |
| 13 | 21489836 |
| 14 | 121517768 |
| 15 | 695307888 |
| 16 | 4019338527 |
| 17 | 23446201495 |
| 18 | 137875318035 |
| 19 | 816646459860 |
| 20 | 4868576661795 |
| 21 | 29196022525905 |
| 22 | 176022384523440 |
| 23 | 1066433501134560 |
| 24 | 6490009520072676 |
| 25 | 39659537885087124 |