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 | 0 |
| 1 | 1 |
| 2 | 4 |
| 3 | 16 |
| 4 | 54 |
| 5 | 176 |
| 6 | 548 |
| 7 | 1667 |
| 8 | 4968 |
| 9 | 14592 |
| 10 | 42348 |
| 11 | 121728 |
| 12 | 347112 |
| 13 | 983173 |
| 14 | 2768812 |
| 15 | 7758928 |
| 16 | 21648546 |
| 17 | 60172784 |
| 18 | 166687436 |
| 19 | 460356359 |
| 20 | 1267964496 |
| 21 | 3483818880 |
| 22 | 9550754520 |
| 23 | 26129950080 |
| 24 | 71356349520 |
| 25 | 194529354505 |
| 26 | 529485228244 |
| 27 | 1439096616976 |
| 28 | 3906061968654 |
| 29 | 10588691040176 |
| 30 | 28670559059444 |