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 | 2 |
| 2 | 4 |
| 3 | 10 |
| 4 | 24 |
| 5 | 60 |
| 6 | 148 |
| 7 | 370 |
| 8 | 920 |
| 9 | 2300 |
| 10 | 5736 |
| 11 | 14340 |
| 12 | 35808 |
| 13 | 89520 |
| 14 | 223668 |
| 15 | 559170 |
| 16 | 1397496 |
| 17 | 3493740 |
| 18 | 8732920 |
| 19 | 21832300 |
| 20 | 54575888 |
| 21 | 136439720 |
| 22 | 341082504 |
| 23 | 852706260 |
| 24 | 2131706864 |
| 25 | 5329267160 |
| 26 | 13322959888 |
| 27 | 33307399720 |
| 28 | 83267756400 |
| 29 | 208169391000 |
| 30 | 520420803060 |
| 31 | 1301052007650 |