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) |
|---|---|
| 1 | 1 |
| 2 | 15 |
| 3 | 106 |
| 4 | 582 |
| 5 | 2952 |
| 6 | 14488 |
| 7 | 69982 |
| 8 | 335356 |
| 9 | 1600624 |
| 10 | 7624266 |
| 11 | 36279784 |
| 12 | 172546968 |
| 13 | 820420150 |
| 14 | 3900386212 |
| 15 | 18541702744 |
| 16 | 88140749906 |
| 17 | 418982915000 |
| 18 | 1991645550032 |
| 19 | 9467293435654 |
| 20 | 45002706816100 |
| 21 | 213919774521224 |
| 22 | 1016864234903874 |
| 23 | 4833646472767104 |