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 | 4 |
| 1 | 18 |
| 2 | 52 |
| 3 | 126 |
| 4 | 280 |
| 5 | 594 |
| 6 | 1228 |
| 7 | 2502 |
| 8 | 5056 |
| 9 | 10170 |
| 10 | 20404 |
| 11 | 40878 |
| 12 | 81832 |
| 13 | 163746 |
| 14 | 327580 |
| 15 | 655254 |
| 16 | 1310608 |
| 17 | 2621322 |
| 18 | 5242756 |
| 19 | 10485630 |
| 20 | 20971384 |
| 21 | 41942898 |
| 22 | 83885932 |
| 23 | 167772006 |
| 24 | 335544160 |
| 25 | 671088474 |
| 26 | 1342177108 |
| 27 | 2684354382 |
| 28 | 5368708936 |
| 29 | 10737418050 |
| 30 | 21474836284 |
| 31 | 42949672758 |
| 32 | 85899345712 |