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 | 9 |
| 4 | 40 |
| 5 | 242 |
| 6 | 1528 |
| 7 | 10664 |
| 8 | 76956 |
| 9 | 575245 |
| 10 | 4395910 |
| 11 | 34131621 |
| 12 | 268146598 |
| 13 | 2122399923 |
| 14 | 16884293154 |
| 15 | 134689290877 |
| 16 | 1075641369024 |
| 17 | 8588548510081 |
| 18 | 68496446989330 |
| 19 | 545303352881863 |
| 20 | 4331918361300882 |
| 21 | 34337864000400360 |
| 22 | 271657823631727330 |
| 23 | 2146133623039711577 |