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) |
|---|---|
| 1 | 1 |
| 2 | 4 |
| 3 | 16 |
| 4 | 64 |
| 5 | 241 |
| 6 | 920 |
| 7 | 3384 |
| 8 | 12585 |
| 9 | 46471 |
| 10 | 172226 |
| 11 | 633138 |
| 12 | 2333757 |
| 13 | 8561679 |
| 14 | 31462176 |
| 15 | 115247629 |
| 16 | 422677188 |
| 17 | 1546186675 |
| 18 | 5661378449 |
| 19 | 20689242550 |
| 20 | 75663420126 |
| 21 | 276279455583 |
| 22 | 1009416896015 |
| 23 | 3683274847187 |
| 24 | 13446591920995 |
| 25 | 49037278586475 |
| 26 | 178904588083788 |
| 27 | 652111697384508 |
| 28 | 2377810831870022 |