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 | 4 |
| 3 | 6 |
| 4 | 21 |
| 5 | 45 |
| 6 | 144 |
| 7 | 378 |
| 8 | 1161 |
| 9 | 3321 |
| 10 | 10044 |
| 11 | 29646 |
| 12 | 89181 |
| 13 | 266085 |
| 14 | 798984 |
| 15 | 2392578 |
| 16 | 7179921 |
| 17 | 21526641 |
| 18 | 64586484 |
| 19 | 193720086 |
| 20 | 581179941 |
| 21 | 1743421725 |
| 22 | 5230324224 |
| 23 | 15690618378 |
| 24 | 47072032281 |
| 25 | 141215033961 |
| 26 | 423645633324 |
| 27 | 1270933711326 |
| 28 | 3812802728301 |
| 29 | 11438398618965 |
| 30 | 34315200639864 |