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 | 20 |
| 1 | 21 |
| 2 | 41 |
| 3 | 144 |
| 4 | 617 |
| 5 | 1995 |
| 6 | 2612 |
| 7 | 4607 |
| 8 | 186892 |
| 9 | 191499 |
| 10 | 378391 |
| 11 | 1326672 |
| 12 | 5685079 |
| 13 | 18381909 |
| 14 | 24066988 |
| 15 | 42448897 |
| 16 | 1722022868 |
| 17 | 1764471765 |
| 18 | 3486494633 |
| 19 | 12223955664 |
| 20 | 52382317289 |
| 21 | 169370907531 |
| 22 | 221753224820 |
| 23 | 391124132351 |
| 24 | 15866718518860 |
| 25 | 16257842651211 |