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 | 3 |
| 2 | 7 |
| 3 | 19 |
| 4 | 49 |
| 5 | 131 |
| 6 | 339 |
| 7 | 899 |
| 8 | 2345 |
| 9 | 6199 |
| 10 | 16225 |
| 11 | 42811 |
| 12 | 112285 |
| 13 | 296051 |
| 14 | 777411 |
| 15 | 2049025 |
| 16 | 5384855 |
| 17 | 14190509 |
| 18 | 37313977 |
| 19 | 98324565 |
| 20 | 258654441 |
| 21 | 681552747 |
| 22 | 1793492411 |
| 23 | 4725856129 |
| 24 | 12439233695 |
| 25 | 32778031159 |
| 26 | 86295460555 |
| 27 | 227399388019 |
| 28 | 598784536563 |
| 29 | 1577923781445 |
| 30 | 4155176578581 |