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 | 3 |
| 1 | 19 |
| 2 | 111 |
| 3 | 647 |
| 4 | 3771 |
| 5 | 21979 |
| 6 | 128103 |
| 7 | 746639 |
| 8 | 4351731 |
| 9 | 25363747 |
| 10 | 147830751 |
| 11 | 861620759 |
| 12 | 5021893803 |
| 13 | 29269742059 |
| 14 | 170596558551 |
| 15 | 994309609247 |
| 16 | 5795261096931 |
| 17 | 33777256972339 |
| 18 | 196868280737103 |
| 19 | 1147432427450279 |
| 20 | 6687726283964571 |
| 21 | 38978925276337147 |
| 22 | 227185825374058311 |