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 | 4 |
| 2 | 13 |
| 3 | 40 |
| 4 | 119 |
| 5 | 350 |
| 6 | 1022 |
| 7 | 2973 |
| 8 | 8635 |
| 9 | 25074 |
| 10 | 72850 |
| 11 | 211875 |
| 12 | 616985 |
| 13 | 1799092 |
| 14 | 5253127 |
| 15 | 15358500 |
| 16 | 44958889 |
| 17 | 131759776 |
| 18 | 386557548 |
| 19 | 1135204289 |
| 20 | 3336791503 |
| 21 | 9816315842 |
| 22 | 28900431835 |
| 23 | 85147344488 |
| 24 | 251030187583 |
| 25 | 740539502786 |