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 | 13 |
| 3 | 44 |
| 4 | 141 |
| 5 | 447 |
| 6 | 1408 |
| 7 | 4428 |
| 8 | 13916 |
| 9 | 43725 |
| 10 | 137373 |
| 11 | 431577 |
| 12 | 1355846 |
| 13 | 4259523 |
| 14 | 13381694 |
| 15 | 42039839 |
| 16 | 132072059 |
| 17 | 414916622 |
| 18 | 1303499025 |
| 19 | 4095062974 |
| 20 | 12865019770 |
| 21 | 40416651612 |
| 22 | 126972655803 |
| 23 | 398896362696 |
| 24 | 1253169882609 |