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) |
|---|---|
| 1 | 1 |
| 2 | 9 |
| 3 | 72 |
| 4 | 320 |
| 5 | 1185 |
| 6 | 3892 |
| 7 | 11776 |
| 8 | 33480 |
| 9 | 90745 |
| 10 | 236808 |
| 11 | 599112 |
| 12 | 1477216 |
| 13 | 3564001 |
| 14 | 8439960 |
| 15 | 19666688 |
| 16 | 45183824 |
| 17 | 102520881 |
| 18 | 230046452 |
| 19 | 511085960 |
| 20 | 1125313056 |
| 21 | 2457641857 |
| 22 | 5327760940 |
| 23 | 11471647872 |
| 24 | 24547187800 |
| 25 | 52225646057 |
| 26 | 110524638672 |