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 | 4 |
| 4 | 10 |
| 5 | 23 |
| 6 | 63 |
| 7 | 155 |
| 8 | 447 |
| 9 | 1150 |
| 10 | 3433 |
| 11 | 9118 |
| 12 | 27923 |
| 13 | 75981 |
| 14 | 237379 |
| 15 | 658380 |
| 16 | 2090519 |
| 17 | 5888530 |
| 18 | 18951534 |
| 19 | 54069881 |
| 20 | 176020213 |
| 21 | 507632647 |
| 22 | 1668910009 |
| 23 | 4857449082 |
| 24 | 16106998656 |
| 25 | 47253245257 |
| 26 | 157874165288 |
| 27 | 466367068388 |
| 28 | 1568587476660 |
| 29 | 4661900731148 |
| 30 | 15773729508730 |