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 | 4 |
| 2 | 8 |
| 3 | 20 |
| 4 | 48 |
| 5 | 116 |
| 6 | 280 |
| 7 | 676 |
| 8 | 1632 |
| 9 | 3940 |
| 10 | 9512 |
| 11 | 22964 |
| 12 | 55440 |
| 13 | 133844 |
| 14 | 323128 |
| 15 | 780100 |
| 16 | 1883328 |
| 17 | 4546756 |
| 18 | 10976840 |
| 19 | 26500436 |
| 20 | 63977712 |
| 21 | 154455860 |
| 22 | 372889432 |
| 23 | 900234724 |
| 24 | 2173358880 |
| 25 | 5246952484 |
| 26 | 12667263848 |
| 27 | 30581480180 |
| 28 | 73830224208 |
| 29 | 178241928596 |
| 30 | 430314081400 |