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) |
|---|---|
| 3 | 120 |
| 4 | 408 |
| 5 | 1200 |
| 6 | 3240 |
| 7 | 8330 |
| 8 | 20720 |
| 9 | 50418 |
| 10 | 120760 |
| 11 | 285846 |
| 12 | 670416 |
| 13 | 1560728 |
| 14 | 3611020 |
| 15 | 8311110 |
| 16 | 19042656 |
| 17 | 43459344 |
| 18 | 98838684 |
| 19 | 224091320 |
| 20 | 506660240 |
| 21 | 1142669766 |
| 22 | 2571214756 |
| 23 | 5773744326 |
| 24 | 12940614624 |
| 25 | 28953267050 |
| 26 | 64676245192 |
| 27 | 144261049680 |
| 28 | 321334401528 |
| 29 | 714843635370 |
| 30 | 1588357198980 |