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 | 2 |
| 3 | 6 |
| 4 | 20 |
| 5 | 42 |
| 6 | 84 |
| 7 | 156 |
| 8 | 312 |
| 9 | 684 |
| 10 | 1020 |
| 11 | 1380 |
| 12 | 1860 |
| 13 | 3480 |
| 14 | 3720 |
| 15 | 4920 |
| 16 | 7320 |
| 17 | 10980 |
| 18 | 14640 |
| 19 | 16920 |
| 20 | 21960 |
| 21 | 26280 |
| 22 | 34920 |
| 23 | 45720 |
| 24 | 59640 |
| 25 | 69840 |
| 26 | 89880 |
| 27 | 106680 |
| 28 | 125160 |
| 29 | 145320 |
| 30 | 177240 |
| 31 | 213360 |
| 32 | 244440 |
| 33 | 269640 |
| 34 | 354480 |
| 35 | 320040 |
| 36 | 375480 |
| 37 | 435960 |
| 38 | 456120 |
| 39 | 531720 |
| 40 | 647640 |