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 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 5 |
| 5 | 23 |
| 6 | 98 |
| 7 | 394 |
| 8 | 1560 |
| 9 | 6181 |
| 10 | 24655 |
| 11 | 99701 |
| 12 | 410513 |
| 13 | 1725725 |
| 14 | 7423757 |
| 15 | 32729320 |
| 16 | 148027044 |
| 17 | 687188969 |
| 18 | 3275077017 |
| 19 | 16022239940 |
| 20 | 80431483586 |
| 21 | 414094461610 |
| 22 | 2185052929580 |
| 23 | 11808696690600 |
| 24 | 65312048149993 |
| 25 | 369408792148714 |
| 26 | 2135111662435080 |
| 27 | 12601466371445619 |