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 | 12 |
| 3 | 32 |
| 4 | 84 |
| 5 | 240 |
| 6 | 784 |
| 7 | 2816 |
| 8 | 10404 |
| 9 | 38096 |
| 10 | 137456 |
| 11 | 493440 |
| 12 | 1783376 |
| 13 | 6532288 |
| 14 | 24245568 |
| 15 | 90814464 |
| 16 | 341776164 |
| 17 | 1289126160 |
| 18 | 4870386736 |
| 19 | 18439692928 |
| 20 | 70004793936 |
| 21 | 266551445952 |
| 22 | 1017708956224 |
| 23 | 3894679004160 |
| 24 | 14932998810896 |
| 25 | 57349426579264 |
| 26 | 220574904103872 |
| 27 | 849571289810432 |